Biological Psychiatry
Original Paper Neuropsychobiology 1992;26:43~49
Olle Hagnell3 Annika Franck3 Anne Gräsbeck3 R o lf Oilman3 L e if Öjesjö3 Lena Olterbeck3 Birgit la Rorsmanb
Vascular Dementia in the Lundby Study 1. A Prospective, Epidemiological Study of Incidence and Risk from 1957 to 1972
3 Department of Psychiatry, and b Department of Psychiatry and Neurochemistry, Lund University, Lund. Sweden
Abstract
The two main forms of dementia among the elderly, senile and vascular dementias, have long been recognized. Both have been frequently described from the early psy chiatric literature onwards. Early investigators of psychiatric disorders, such as Bonhoeffcr. Kraepelin and Alzheimer, realized the im portance of studies in the field of degenerative brain dis orders. Much of their interest arose from the search for links between psychiatric symptomatology and specific morphological components. Later, for quite a long period, this research area became unfashionable and was largely neglected. Among those who rediscovered and had the foresight to promote it was Sir Martin Roth who, in publi cations in the 1950s. re-emphasized the importance of a diagnostic approach for better differentiating various forms of mental diseases among the elderly. He realized that the growth of the aged population in society was becoming a vast medical as well as political problem.
Interest in the nosology and origin of disease in the elderly was once more a challenge to psychiatric research. In recent decades the increasing population of aged individuals at risk for dementia disorders has become a growing concern to those providing social and medical support. Even if the neurosciences have brought new tools for research, the demarcation lines between various forms of dementia are not clear in clinical practice. The total Lundby study covers, at present, a 40-year perspective of mental health in a normal Swedish popula tion, and comprises social as well as psychiatric aspects. Over the years we have returned to this population in a large number of publications to report on the incidence and prevalence of degenerative disorders of the aged [113], Incidence studies of vascular dementia covering a total population are still scarce. The present study gives the 15year (1957-1972) incidence of vascular dementia in the 1957 cohort of the total Lundby population, and provides the basic data for the search for background factors.
This study was performed with the approval of the Ethical Committee o f the Lund University Faculty o f Medicine and with the permission of the Swedish Data Inspection Board.
Prof. Olle Hagnell The Lundby Projcct Sl. Lars Sjukhus Box 646
Introduction
© 1992 S. Karger AG. Basel 0302-282X/92/0262-0043 $2.75/0
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KeyWords Vascular dementia Prospective Longitudinal Incidence, Lundby study
In this study, a total population, the 1957 Lundby cohort, was investigated with regard to the incidence of vascular dementia over a 15-year period, and to provide a succeeding study with basic data concerning the background fac tors for vascular dementia. The 1957 cohort comprises 2,612 persons who were registered in the geographically delimited Lundby area on July 1, 1957. The lifetime risk of developing vascular dementia was found to be 34.5% in men and 19.4% in women when all degrees of impairment were taken into account, the preponderance for the male sex being very obvious.
Table 1. Survey of the 1957 Lundbv cohort on July l. I957
Materials and Methods
(n = 2,6l2)
Men
Remaining from 1947 cohort
Total
147 105 86 138 158 88 63 39
169 69 65 84 55 43 11 7 8
169 216 170 170 193 201 99 70 47
824
511
1.335
139 69 75 137 140 1 13 74 28
171 70 80 75 52 32 10 8 4
171 209 149 150 189 172 123 82 32
775
502
1.277
1,599
1.013
2.612
_
0-9 10-19 20-29 30-39 40-49 50-59 60-69 70-79 80+
Total
Women
Newcomers in 1957
0-9 10-19 20-29 30-39 40-49 50-59 60-69 70-79 80+
-
Total Overall total of cohort
Table 2. Number of living and deceased persons on July I. I972. by age and sex. in the Lundby 1957 cohort
Age in 1957 years 0-9 10-19 20-29 30-39 40-49 50-59 60-69 70-79 80+ Total
44
Men
Women
alive
deceased
alive
deceased
167 213 166 166 173 156 48 8 1
2 3 4 4 15 45 51 62 46
171 208 148 145 180 147 73 21
-
1 1 5 9 25 50 61 32
1.103
232
1,093
184
_
This particular study covers the 2,612 individuals who, on July 1. 1957, were registered in Lundby. a geographically delimited area in southern Sweden. The area is identical with the one investigated in 1947 by Essen-Molleret al. [I]. The 1957 cohort, the population sam ple of this study, is unlike the original cohort of 1947. Almost 1.000 persons had dropped out: 700 by emigration from the area and 253 by death. O f the 1.013 newcomers. 340 were children under the age of 10 years, most of them born to parents belonging to the 1947 cohort (table 1). In 1957 all the probands were examined by one psy chiatrist. Hagnell [2], In 1972. still with the same cross-section date, the same persons were reinvestigated by Hagnell and Ojesjo. irre spective of domicile. For those 416 who had died during the period (table 2), enough information was collected from relatives and other sources for an evaluation of their health. For a closer description of the procedure of the 1972 study, sec Hagnell et al. [9], In all the field investigations the non-response figure could be kept very low, 1-2%. Information was collected through personal examinations by experienced psychiatrists and from supplementary sources such as various official registers, hospital case notes, and key informants. For the degree of success in collecting the 1972 informa tion. see table 3. The percentage of sufficient information about those who died during the period is shown in table 4. The personal examination of the probands usually took place in their homes. The old people, however, were often found living with relatives or in institutions. The psychiatrist wrote down the pro band’s history about his/her mental and physical health, social rela tions. professional career, and socio-economic background. Then fol lowed a semi-structured interview based on a file of items with the aim of describing the proband's behaviour, personality, and mental traits. The subject usually regarded the examination as finished when the examiner put away paper and pencil. A relaxed chat afterwards often resulted in important additional information. The principles of classification were given in the 1957 report of the Lundby study [2] and have remained the same throughout the years [9], In the early 1980s our cases of age psychosis were re-evalu ated according to Roth’s organic brain syndrome [14. 15] as either senile or multi-infarct dementia (MID). Due to the heterogeneity of the latter group o f disorders we now prefer the term vascular demen tia instead of MID which has become restricted to a certain subgroup of dementias. Compared with modern criteria our concept of vascu lar dementia broadly corresponds to the MID of the DSM-III-R [ 16] and to the arteriosclerotic dementia of ICD-9 [17], People with focal neurological signs and symptoms were always placed in the vascular group, whether the differential diagnosis was hard to state or they could be regarded as mixed cases. We are quite aware that focal symptoms may appear in disorders other than vascular dementia, but in a large population survey like this one. it is impossible to per form a complete clinical examination. Further, the diagnostic tools used nowadays were not available at the time of our field investiga tion. The first signs of illness were often reported by those in the imme diate environment of the sick person. Those who knew the person well gave important information about changes in personality traits, physical and mental health, and social conditions. This was particu larly important in the cases of dementia, because their illness often made them unable to contribute to their anamnesis themselves. The degree of impairment was rated as severe, medium or mild in accordance with the previous Lundby study [2,9].
H agnell/F ra nck/G räsbeck/Öh man/Öjesjö/ Otterbeck/Rorsman
Vascular Dementia in the Lundby Study
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Age in 1957 years
Table 3. Survivors of the 1957 Lundby cohort interviewed or suf ficiently known in 1972. distributed by sex and age (n = 2.612)
Age in 1972 Alive years in 1972 n
Men
Case I He was a farmer, a kind and decent man. At the age of 54 he was taken ill with cncephaloineningitis. and ran a high temperature for weeks. He was confused and lost his memory for one entire week. Very tired afterwards, it look about a year until he felt healthy again. Between two of our examinations, when he was 50 and 60 years of age. w'e noticed a change. At the age of 60 he had become tense, almost shaky, and suffered from vegetative lability. He was very cir cumspect, diverging from the topic again and again. He seemed a little tired, and showed affective lability. He thought himself quite unchanged, but his relatives had noted the changes described. At the age of 70 he suddenly became weak in his right arm and leg. His speech was slurred for a day and he was bedridden for a week. After this episode he was unable to walk without crutches. The same year he was hospitalized for heart failure. He had repeated epi sodes of hemiplegia, and later hemiparesis. facial paresis, and expres sive aphasia. His mental state deteriorated, and he had a loss of grasp. He was forgetful, until he could not remember if he had had dinner or not half an hour later. He became more and more confused. The aphasia made him cry when he was unable to express himself. His state varied but during his last years he was unable to take care of himself, and was totally helpless. Eventually, it became impossible to take care of him at home in spite of the fact that relatives worked very hard trying to do so. He spent his last years in a nursing home where he languished away. Death diagnosis: pneumonia + infarctus cerebri cum hemiparesis dx. Evaluation. Lundby: vascular dementia, severe impairment. Cor responding to ICD-9 290.4 and DMS-III-R 290.40.
With enough information in 1972
n
n
627 172 191 87 26
619 172 191 83 20
1.103
% 98.7
% 99.8
95.4 76.9
626 172 191 86 26
1.085
98.4
1,101
99.8
608 144 177 115 49
603 144 177 113 43
99.2 100.0 100.0 98.3 87.8
605 144 177 115 49
99.5 100.0
Total
1.093
1.080
98.8
1,090
99.7
Overall total of cohort
2,196
2.165
98.6
2.191
99.8
Total
Women
The Concept o f Vascular Dementia in the Lundhy Study The essential feature is a loss of cognitive abilities of sufficient severity to interfere with social or occupational functioning. The deficit is multifaceted and involves memory, judgement, abstract thought, and a variety of other higher cortical functions. Changes in personality and behaviour also occur. For a few cases, vascular dementia may be impossible to separate from senile dementia of the Alzheimer type (SDAT). Only probands with focal symptoms were included in the vascular group. The other symptoms from the central nervous system may vary in degree. At least at the beginning of the disease there are more florid symptoms. To further illustrate the concept o f vascular dementia in this study, two case histories are given below.
0-49 50-59 60-69 70-79 80+
Personally examined in 1972
0-49 50-59 60-69 70-79 80+
100.0 100.0
100.0 100.0 98.9
100.0
100.0 100.0 100.0
Table 4. Survey of residence and information obtained in 1972 for the 1957 Lundby cohort (n = 2,612)
Residence in 1972
Number
Personally examined in 1972
With enough information in 1972
n
%
n
%
Men In = 1,335) Remaining in 1972 Moved 1957-1972 Deceased 1957-1972
715 388 232
708 377 -
99.0 97.2 -
715 386 227
100.0 99.5 97.8
Women (n = 1,277) Remaining in 1972 Moved 1957-1972 Deceased 1957-1972
667 426 184
661 419 -
99.1 98.4 -
667 423 178
100.0 99.3 96.7
Case 2 She was married to a farmer and enjoyed living in the country'. She had one child. At the age of 40 she underwent bilateral salpingooophorectomy because of ovarian cysts. In her fifties she devel oped angina pectoris and hypertension and had to take medicine. At both personal interviews, when she was 51 and 61 years old. she gave the impression of being a calm and gentle woman. Spontaneous and enterprising, though somewhat fragile in constitution, she was con sidered to be in perfect mental health. At the third survey in 1972 she had recently died and information was based on outside reports.
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Severe impairment involves contusion and a pronounced loss of memory together with a marked reduction in functional capacity. People in this group need total 24-hour care. Medium impairment is not sharply delimited from severe or mild impairment. The pro band depends on help for daily activities. Mild impairment means that daily work is usually possible although with lowered achieve ment. It should be emphasized that the mild group does not include borderline cases: rather, even mildly impaired subjects had symptoms of such a degree that the evaluating psychiatrist consid ered their mental condition to be definitely pathological and of clinical significance, requiring therapeutic intervention and daily supervision. When in doubt about a person’s health or sickness, we always chose the healthier alternative. A few probands with incipi ent vascular dementia may in this way have been excluded, but on the other hand we can be sure that the frequencies shown arc not exaggerated.
Table 5. The incidence and risk of contracting severe vascular dementia during the 15-year period 1957-1972
Age group years
Men
0-49 50-59 60-69 70-79 80-89 90-99 100+
Total
Women
Total
0-49 50-59 60-69 70-79 80-89 90-99 100+
Observation years under risk
Cases
Rate per year
Probability of disease during age interval
Cumulative probability of disease
11.490.5 3.005.3 2.196.0 1.117.0 459.7 67.7 0
0 0 3 3 6 0 0
0.0000(0.0000) 0.0000 (0.0000) 0.0014(0.0008) 0.0027(0.0016) 0.0131 (0.0053) 0.0000 (0.0000) 0.0000 (0.0000)
0.000 (0.000) 0.000 (0.000) 0.014(0.008) 0.027(0.015) 0.122 (0.047)
0.000 (0.000) 0.000 (0.000) 0.014(0.008) 0.040(0.017) 0.157(0.047)
-
-
-
-
18.336.2
12
0.0005 (0.0001)
-
-
10.848.5 2,686.6 2,267.8 1.343.0 522.5 66.8 2.6
0 0 1 7 4 0 0
0.0000(0.0000) 0.0000(0.0000) 0.0004 (0.0004) 0.0052 (0.0020) 0.0077 (0.0038) 0.0000(0.0000) 0.0000(0.0000)
0.000 (0.000) 0.000 (0.000) 0.004 (0.004) 0.051 (0.019) 0.074 (0.035)
0.000 (0.000) 0.000 (0.000) 0.004 (0.004) 0.055(0.019) 0.125 (0.038)
-
-
-
-
17.737.8
12
0.0006 (0.0002)
-
-
Values in parentheses are SE.
Statistical Method The first step in our statistical procedure was to determine, for each person involved, a period of risk. In the absence o f any episode of the illness in question before July 1, 1957, the risk period starts on that date; however, if such a previous episode has occurred, no risk period exists at all. Then the period, if any. lasts until July 1. 1972,
46
death or onset o f illness, whichever occurs first. Note that the start of an episode once and for all terminates the risk period (as vascular dementia must be regarded as a chronic disease). The risk period is then divided into segments, a new' segment beginning when the per son enters a new 10-year age group. Finally the results are aggregated over the entire cohort, i.e. for every age group the lengths of all risk period segments in the age group are added together. I n the same way the number of first episodes of vascular dementia is counted for each age group. During both these aggregation procedures the two sexes are treated separately. The reader interested in statistics is referred to Rorsman et al. [ 18] for further details of the method used.
Results
The incidence and risk of contracting vascular demen tia based on data from a total population, the Lundby 1957 cohort, during the period 1957-1972. arc given in tables 5-7. 58 probands developed vascular dementia during the 15-year period. The distribution of ages, sexes, and degrees of impairment of the illness are given in the tables. When all the degrees of impairment were taken together, considerably more men than women developed vascular dementia. Only the severe form showed no dif ferences between the sexes.
Hagnell/Franck/Gräsbeck/Öhman/Öjesjö/ Otterbeck/Rorsman
Vascular Dementia in the Lundby Study
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According to her daughter she was the type of person who never complained. When her husband died, she took it with composure. She left her home and moved to her daughter in another town. Later she had an attack of herpes zoster involving the left side of her face and the inside of her mouth and ear and, according to her daughter, she never really was herself after that. She was tired and feeble and had difficul ties in walking, largely because of arthritis in her knees. For many years she had been occasionally absent-minded, seeming completely lost to her surroundings for about ten minutes before returning to nor mal. She became more and more forgetful. For example, she did not always remember that her husband was dead. She became increasingly taciturn and could not control her bladder and bowel. At the age of 74 she had a cerebral thrombosis and was admitted to hospital with right-sided hemiplegia including the facial nerve. She was somnolent and had difficulties in articulating. She was treated with corticosteroids and physiotherapy but made only moderate improvement and was merely able to sit beside her bed during the daytime. She answered when she was spoken to but was not fully oriented in her mind. Evaluation. Lundby: vascular dementia, medium impairment. Corresponding to ICD-9 290.4 and DSM-III-R 290.40
Table 6. The incidence and risk of contracting severe and medium vascular dementias during the 15-year period
1957-1972 Age group years
Men
0-49 50-59 60-69 70-79 80-89 90-99 100+
Total
Women
0-49 50-59 60-69 70-79 80-89 90-99 100+
Total
Observation years under risk
Cases
Rate per year
Probability of disease during age interval
Cumulative probability of disease
0.000 (0.000) 0.007 (0.005) 0.045(0.014) 0.053(0.021) 0.225 (0.060)
0.000 (0.000) 0.007 (0.005) 0.051 (0.015) 0.102(0.024) 0.304(0.057)
-
-
-
-
11,490.5 3.002.7 2,168.9 1.095.9 432.1 62.9 0
0 2 10 6 11 3 0
0.0000 (0.0000) 0.0007 (0.0005) 0.0046(0.0015) 0.0055 (0.0022) 0.0255 (0.0077) 0.0477(0.0275) 0.0000 (0.0000)
18,253.0
32
0.0012(0.0002)
-
-
10.848.5 2.686.6 2.267.8 1.330.0 517.9 66.8 2.6
0 0 1 14 5 0 0
0.0000 (0.0000) 0.0000 (0.0000) 0.0004 (0.0004) 0.0105 (0.0028) 0.0097 (0.0043) 0.0000(0.0000) 0.0000 (0.0000)
0.000 (0.000) 0.000 (0.000) 0.004 (0.004) 0.100(0.025) 0.092 (0.039)
0.000 (0.000) 0.000 (0.000) 0.004 (0.004) 0.104(0.026) 0.186(0.042)
-
-
-
-
17.720.2
20
0.0009 (0.0002)
-
-
Values in parentheses are SE.
Table 7. The incidence and risk of contracting severe, medium and mild vascular dementias during the 15-year period 1957-1972
Age group years
Men
0-49 50-59 60-69 70-79 80-89 90-99 100+
Total
Women
Total
0-49 50-59 60-69 70-79 80-89 90-99 100+
Observation years under risk
Cases
Rate per year
Probability of disease during age interval
Cumulative probability of disease
0.000 (0.000) 0.007(0.005) 0.054(0.015) 0.054(0.021) 0.263(0.062)
0.000(0.000) 0.007 (0.005) 0.060 (0.016) 0.111 (0.025) 0.345 (0.058)
-
-
-
-
11.490.5 3,002.7 2.166.4 1,089.2 425.5 62.9 0
0 2 12 6 13 3 0
0.0000(0.0000) 0.0007 (0.0005) 0.0055(0.0016) 0.0055 (0.0022) 0.0306 (0.0085) 0.0477(0.0275) 0.0000 (0.0000)
18,237.2
36
0.0013(0.0002)
-
-
10,848.5 2.686.6 2,261.0 1.329.0 512.5 63.8 2.6
0 0 3 14 5 0 0
0.0000 (0.0000) 0.0000(0.0000) 0.0013(0.0008) 0.0105(0.0028) 0.0098 (0.0044) 0.0000(0.0000) 0.0000(0.0000)
0.000 (0.000) 0.000 (0.000) 0.013(0.008) 0.100 (0.025) 0.093 (0.040)
0.000 (0.000) 0.000 (0.000) 0.013(0.008) 0.112(0.026) 0.194 (0.042)
-
-
-
-
17,704.0
22
0.0010(0.0002)
-
-
47
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Values in parentheses are SE.
Discussion
Over a long period of time the aged individuals have formed a rapidly increasing segment of the population of the developed countries. A similar change is in progress in most developing countries [ 19], In the Lundby study, vas cular dementia is by far the most common mental illness in men > 60 years of age. the incidence rate being 9 .1 per 1,000 person years, while in women in the same age groups depression clearly dominates with an incidence rate of 8.2 per 1.000 person years. SDAT is the second most common disease in both men and women among the elderly in this population, the incidence rate being 5.0 and 5.5 per 1,000 person years, respectively. A good many of the men develop vascular dementia as early as their sixties, while women are more often affected in their seventies. In the age range 80-89. men again dom inate (table 7). Looking at the cumulative risk up to age 90 of developing vascular dementia one finds that the male predominance is evident, but only when the less severe types are considered. When the same Lundby cohort was investigated with regard to the incidence of SDAT [10], no sex difference was found. However, combined data from community surveys show a tendency towards a female predominance in SDAT and a male one in vascular dementia [20]. Hence, prevalence data from the EURODEM research programme point towards a male dominance of vascular dementia, except for the age group of 80-89, where the Lundby study and a Finnish one showed a female pre dominance. While the 1957 Lundby prevalence data showed a slight weighting towards men. the correspond ing 1972 data changed into a weighting towards women in this age group because of a steeper decrease in men
than in women. The question has been raised whether this was due to a true increase in incidence [12]. The preva lence data referred to do not. contrary to our incidence figures, take into account the events that occurred during the 15-year period, such as deaths. There are certain find ings indicating that men develop their dementia and die earlier than women [21]. This would to a certain extent explain the high prevalence and incidence found among the old women [ 12]. The provision of medical and social welfare for the aged individual has become a matter of great concern for all society. The question has not only large economic implications, it should also be seen against a background of social structure, where the multiple generation family is no longer a way of life. Social reforms and medical inter vention, however, have aimed at preventing impairment among the elderly and providing alternatives in care. Lon gitudinal population studies, based on incidence data, will best reflect the results of such efforts. Incidence data give more reliable information about changes over time and differences between the sexes, and we are now col lecting data for an incidence study up to 1992. Finding relevant background factors, the topic of the succeeding article, could in turn provide opportunities for pre vention.
Acknowledgements Our sincere thanks to J. Lanke for the statistical work, and to R.G. Dewsnap for revising the manuscript. This study was supported by the follow ing grants: the Bank of Sweden Tercentenary Founda tion No. 71/2; the Swedish Medical Research Council No. 3474. 4803. 6008,6881: the Swedish Ministry of Health and Social Affairs. Delegation for Social Research No. 83/64: 1-2.
References
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4 Hagnell O. Lanke J. Rorsman B. et al: Current trends in the incidence of senile and multi infarct dementia. A prospective study of a total population followed over 25 years: the Lundby study. Arch Psychiatr Nervenkr 1983:233: 423-438. 5 Rorsman B. Hagnell O. Lanke J: Prevalence of age psychosis and mortality among age psychotics in the Lundby study: changes over time during a 25-year observation period. Neuropsychobiology 1985:13:167-172.
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Vascular Dementia in the Lundby Study
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1 Essen-Möller E. Larsson H. Uddenbcrg CE. White G: Individual traits and morbidity in a Swedish rural population. Acta Psychiatr Neu rol Scand Suppl l956;(Suppl 100). 2 Hagnell O: A Prospective Study of the Inci dence of Mental Disorder. Lund. Svenska Bokforlaget. 1966. 3 Hagnell O. Lanke J. Rorsman B. et al: Does the incidence of age psychosis decrease? A prospec tive longitudinal study of a complete popula tion investigated during the 25-year period 1947-1972: The Lundby study. Neuropsycho biology 1981:7:201-211.
12 Rocca WA. Hofman A. Brayne C. et al: The prevalence of vascular dementia in Europe. A collaborative study of 1980-1990 findings. Re port from the EURODEM-prevalcnce project. Ann Neurol 1991;6:817-824. 13 Hagncll O. Franck A. Grasbeck A. et al: Senile dementia Alzheimer type in the Lundby Study. II. An attempt to identify possible risk factors. Eur Arch Psychiatry Clin Neurosci. 1992:241: 231-235. 14 Roth M: The natural history of mental disorder in old age. J Ment Sci 1955;101:281-301. 15 Roth M: The diagnosis o f dementia in late and middle life: in Mortimer JA. Schuman I.M (eds): The Epidemiology of Dementia. New York. Oxford University Press. 1981. pp 2461. 16 American Psychiatric Association: Diagnostic and Statistical Manual of Mental Disorders, ed 3. revised. Washington. American Psychiatric Association. 1987.
17 World Health Organization: International Classification of Diseases, ninth revision. Ge neva, World Health Organization. 1978. 18 Rorsman B. Grasbeck A. Hagncll O. et al: A prospective study of first-incidence depression. The Lundby study 1957-1972. BrJ Psychiatry 1990:156:336-342. 19 United Nations: World population prospects: Estimates and projections as assessed in 1982. Department of International Economic and Social Affairs. Population studies No. 86 ST/ ESA,'SLR a/86. New York. United Nations. 1985. 20 Kay DWK: The epidemiology of dementia: A review of recent work. Rev Clin Gerontol 1991;1:55-66. 21 Nilsson LV: Incidence of severe dementia in an urban sample followed from 70 to 79 years of age. Acta Psvchiair Scand 1984:70:478-486.
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Original Paper Neuropsychobiology 1992;26:43~49
Olle Hagnell3 Annika Franck3 Anne Gräsbeck3 R o lf Oilman3 L e if Öjesjö3 Lena Olterbeck3 Birgit la Rorsmanb
Vascular Dementia in the Lundby Study 1. A Prospective, Epidemiological Study of Incidence and Risk from 1957 to 1972
3 Department of Psychiatry, and b Department of Psychiatry and Neurochemistry, Lund University, Lund. Sweden
Abstract
The two main forms of dementia among the elderly, senile and vascular dementias, have long been recognized. Both have been frequently described from the early psy chiatric literature onwards. Early investigators of psychiatric disorders, such as Bonhoeffcr. Kraepelin and Alzheimer, realized the im portance of studies in the field of degenerative brain dis orders. Much of their interest arose from the search for links between psychiatric symptomatology and specific morphological components. Later, for quite a long period, this research area became unfashionable and was largely neglected. Among those who rediscovered and had the foresight to promote it was Sir Martin Roth who, in publi cations in the 1950s. re-emphasized the importance of a diagnostic approach for better differentiating various forms of mental diseases among the elderly. He realized that the growth of the aged population in society was becoming a vast medical as well as political problem.
Interest in the nosology and origin of disease in the elderly was once more a challenge to psychiatric research. In recent decades the increasing population of aged individuals at risk for dementia disorders has become a growing concern to those providing social and medical support. Even if the neurosciences have brought new tools for research, the demarcation lines between various forms of dementia are not clear in clinical practice. The total Lundby study covers, at present, a 40-year perspective of mental health in a normal Swedish popula tion, and comprises social as well as psychiatric aspects. Over the years we have returned to this population in a large number of publications to report on the incidence and prevalence of degenerative disorders of the aged [113], Incidence studies of vascular dementia covering a total population are still scarce. The present study gives the 15year (1957-1972) incidence of vascular dementia in the 1957 cohort of the total Lundby population, and provides the basic data for the search for background factors.
This study was performed with the approval of the Ethical Committee o f the Lund University Faculty o f Medicine and with the permission of the Swedish Data Inspection Board.
Prof. Olle Hagnell The Lundby Projcct Sl. Lars Sjukhus Box 646
Introduction
© 1992 S. Karger AG. Basel 0302-282X/92/0262-0043 $2.75/0
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KeyWords Vascular dementia Prospective Longitudinal Incidence, Lundby study
In this study, a total population, the 1957 Lundby cohort, was investigated with regard to the incidence of vascular dementia over a 15-year period, and to provide a succeeding study with basic data concerning the background fac tors for vascular dementia. The 1957 cohort comprises 2,612 persons who were registered in the geographically delimited Lundby area on July 1, 1957. The lifetime risk of developing vascular dementia was found to be 34.5% in men and 19.4% in women when all degrees of impairment were taken into account, the preponderance for the male sex being very obvious.
Table 1. Survey of the 1957 Lundbv cohort on July l. I957
Materials and Methods
(n = 2,6l2)
Men
Remaining from 1947 cohort
Total
147 105 86 138 158 88 63 39
169 69 65 84 55 43 11 7 8
169 216 170 170 193 201 99 70 47
824
511
1.335
139 69 75 137 140 1 13 74 28
171 70 80 75 52 32 10 8 4
171 209 149 150 189 172 123 82 32
775
502
1.277
1,599
1.013
2.612
_
0-9 10-19 20-29 30-39 40-49 50-59 60-69 70-79 80+
Total
Women
Newcomers in 1957
0-9 10-19 20-29 30-39 40-49 50-59 60-69 70-79 80+
-
Total Overall total of cohort
Table 2. Number of living and deceased persons on July I. I972. by age and sex. in the Lundby 1957 cohort
Age in 1957 years 0-9 10-19 20-29 30-39 40-49 50-59 60-69 70-79 80+ Total
44
Men
Women
alive
deceased
alive
deceased
167 213 166 166 173 156 48 8 1
2 3 4 4 15 45 51 62 46
171 208 148 145 180 147 73 21
-
1 1 5 9 25 50 61 32
1.103
232
1,093
184
_
This particular study covers the 2,612 individuals who, on July 1. 1957, were registered in Lundby. a geographically delimited area in southern Sweden. The area is identical with the one investigated in 1947 by Essen-Molleret al. [I]. The 1957 cohort, the population sam ple of this study, is unlike the original cohort of 1947. Almost 1.000 persons had dropped out: 700 by emigration from the area and 253 by death. O f the 1.013 newcomers. 340 were children under the age of 10 years, most of them born to parents belonging to the 1947 cohort (table 1). In 1957 all the probands were examined by one psy chiatrist. Hagnell [2], In 1972. still with the same cross-section date, the same persons were reinvestigated by Hagnell and Ojesjo. irre spective of domicile. For those 416 who had died during the period (table 2), enough information was collected from relatives and other sources for an evaluation of their health. For a closer description of the procedure of the 1972 study, sec Hagnell et al. [9], In all the field investigations the non-response figure could be kept very low, 1-2%. Information was collected through personal examinations by experienced psychiatrists and from supplementary sources such as various official registers, hospital case notes, and key informants. For the degree of success in collecting the 1972 informa tion. see table 3. The percentage of sufficient information about those who died during the period is shown in table 4. The personal examination of the probands usually took place in their homes. The old people, however, were often found living with relatives or in institutions. The psychiatrist wrote down the pro band’s history about his/her mental and physical health, social rela tions. professional career, and socio-economic background. Then fol lowed a semi-structured interview based on a file of items with the aim of describing the proband's behaviour, personality, and mental traits. The subject usually regarded the examination as finished when the examiner put away paper and pencil. A relaxed chat afterwards often resulted in important additional information. The principles of classification were given in the 1957 report of the Lundby study [2] and have remained the same throughout the years [9], In the early 1980s our cases of age psychosis were re-evalu ated according to Roth’s organic brain syndrome [14. 15] as either senile or multi-infarct dementia (MID). Due to the heterogeneity of the latter group o f disorders we now prefer the term vascular demen tia instead of MID which has become restricted to a certain subgroup of dementias. Compared with modern criteria our concept of vascu lar dementia broadly corresponds to the MID of the DSM-III-R [ 16] and to the arteriosclerotic dementia of ICD-9 [17], People with focal neurological signs and symptoms were always placed in the vascular group, whether the differential diagnosis was hard to state or they could be regarded as mixed cases. We are quite aware that focal symptoms may appear in disorders other than vascular dementia, but in a large population survey like this one. it is impossible to per form a complete clinical examination. Further, the diagnostic tools used nowadays were not available at the time of our field investiga tion. The first signs of illness were often reported by those in the imme diate environment of the sick person. Those who knew the person well gave important information about changes in personality traits, physical and mental health, and social conditions. This was particu larly important in the cases of dementia, because their illness often made them unable to contribute to their anamnesis themselves. The degree of impairment was rated as severe, medium or mild in accordance with the previous Lundby study [2,9].
H agnell/F ra nck/G räsbeck/Öh man/Öjesjö/ Otterbeck/Rorsman
Vascular Dementia in the Lundby Study
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Age in 1957 years
Table 3. Survivors of the 1957 Lundby cohort interviewed or suf ficiently known in 1972. distributed by sex and age (n = 2.612)
Age in 1972 Alive years in 1972 n
Men
Case I He was a farmer, a kind and decent man. At the age of 54 he was taken ill with cncephaloineningitis. and ran a high temperature for weeks. He was confused and lost his memory for one entire week. Very tired afterwards, it look about a year until he felt healthy again. Between two of our examinations, when he was 50 and 60 years of age. w'e noticed a change. At the age of 60 he had become tense, almost shaky, and suffered from vegetative lability. He was very cir cumspect, diverging from the topic again and again. He seemed a little tired, and showed affective lability. He thought himself quite unchanged, but his relatives had noted the changes described. At the age of 70 he suddenly became weak in his right arm and leg. His speech was slurred for a day and he was bedridden for a week. After this episode he was unable to walk without crutches. The same year he was hospitalized for heart failure. He had repeated epi sodes of hemiplegia, and later hemiparesis. facial paresis, and expres sive aphasia. His mental state deteriorated, and he had a loss of grasp. He was forgetful, until he could not remember if he had had dinner or not half an hour later. He became more and more confused. The aphasia made him cry when he was unable to express himself. His state varied but during his last years he was unable to take care of himself, and was totally helpless. Eventually, it became impossible to take care of him at home in spite of the fact that relatives worked very hard trying to do so. He spent his last years in a nursing home where he languished away. Death diagnosis: pneumonia + infarctus cerebri cum hemiparesis dx. Evaluation. Lundby: vascular dementia, severe impairment. Cor responding to ICD-9 290.4 and DMS-III-R 290.40.
With enough information in 1972
n
n
627 172 191 87 26
619 172 191 83 20
1.103
% 98.7
% 99.8
95.4 76.9
626 172 191 86 26
1.085
98.4
1,101
99.8
608 144 177 115 49
603 144 177 113 43
99.2 100.0 100.0 98.3 87.8
605 144 177 115 49
99.5 100.0
Total
1.093
1.080
98.8
1,090
99.7
Overall total of cohort
2,196
2.165
98.6
2.191
99.8
Total
Women
The Concept o f Vascular Dementia in the Lundhy Study The essential feature is a loss of cognitive abilities of sufficient severity to interfere with social or occupational functioning. The deficit is multifaceted and involves memory, judgement, abstract thought, and a variety of other higher cortical functions. Changes in personality and behaviour also occur. For a few cases, vascular dementia may be impossible to separate from senile dementia of the Alzheimer type (SDAT). Only probands with focal symptoms were included in the vascular group. The other symptoms from the central nervous system may vary in degree. At least at the beginning of the disease there are more florid symptoms. To further illustrate the concept o f vascular dementia in this study, two case histories are given below.
0-49 50-59 60-69 70-79 80+
Personally examined in 1972
0-49 50-59 60-69 70-79 80+
100.0 100.0
100.0 100.0 98.9
100.0
100.0 100.0 100.0
Table 4. Survey of residence and information obtained in 1972 for the 1957 Lundby cohort (n = 2,612)
Residence in 1972
Number
Personally examined in 1972
With enough information in 1972
n
%
n
%
Men In = 1,335) Remaining in 1972 Moved 1957-1972 Deceased 1957-1972
715 388 232
708 377 -
99.0 97.2 -
715 386 227
100.0 99.5 97.8
Women (n = 1,277) Remaining in 1972 Moved 1957-1972 Deceased 1957-1972
667 426 184
661 419 -
99.1 98.4 -
667 423 178
100.0 99.3 96.7
Case 2 She was married to a farmer and enjoyed living in the country'. She had one child. At the age of 40 she underwent bilateral salpingooophorectomy because of ovarian cysts. In her fifties she devel oped angina pectoris and hypertension and had to take medicine. At both personal interviews, when she was 51 and 61 years old. she gave the impression of being a calm and gentle woman. Spontaneous and enterprising, though somewhat fragile in constitution, she was con sidered to be in perfect mental health. At the third survey in 1972 she had recently died and information was based on outside reports.
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Severe impairment involves contusion and a pronounced loss of memory together with a marked reduction in functional capacity. People in this group need total 24-hour care. Medium impairment is not sharply delimited from severe or mild impairment. The pro band depends on help for daily activities. Mild impairment means that daily work is usually possible although with lowered achieve ment. It should be emphasized that the mild group does not include borderline cases: rather, even mildly impaired subjects had symptoms of such a degree that the evaluating psychiatrist consid ered their mental condition to be definitely pathological and of clinical significance, requiring therapeutic intervention and daily supervision. When in doubt about a person’s health or sickness, we always chose the healthier alternative. A few probands with incipi ent vascular dementia may in this way have been excluded, but on the other hand we can be sure that the frequencies shown arc not exaggerated.
Table 5. The incidence and risk of contracting severe vascular dementia during the 15-year period 1957-1972
Age group years
Men
0-49 50-59 60-69 70-79 80-89 90-99 100+
Total
Women
Total
0-49 50-59 60-69 70-79 80-89 90-99 100+
Observation years under risk
Cases
Rate per year
Probability of disease during age interval
Cumulative probability of disease
11.490.5 3.005.3 2.196.0 1.117.0 459.7 67.7 0
0 0 3 3 6 0 0
0.0000(0.0000) 0.0000 (0.0000) 0.0014(0.0008) 0.0027(0.0016) 0.0131 (0.0053) 0.0000 (0.0000) 0.0000 (0.0000)
0.000 (0.000) 0.000 (0.000) 0.014(0.008) 0.027(0.015) 0.122 (0.047)
0.000 (0.000) 0.000 (0.000) 0.014(0.008) 0.040(0.017) 0.157(0.047)
-
-
-
-
18.336.2
12
0.0005 (0.0001)
-
-
10.848.5 2,686.6 2,267.8 1.343.0 522.5 66.8 2.6
0 0 1 7 4 0 0
0.0000(0.0000) 0.0000(0.0000) 0.0004 (0.0004) 0.0052 (0.0020) 0.0077 (0.0038) 0.0000(0.0000) 0.0000(0.0000)
0.000 (0.000) 0.000 (0.000) 0.004 (0.004) 0.051 (0.019) 0.074 (0.035)
0.000 (0.000) 0.000 (0.000) 0.004 (0.004) 0.055(0.019) 0.125 (0.038)
-
-
-
-
17.737.8
12
0.0006 (0.0002)
-
-
Values in parentheses are SE.
Statistical Method The first step in our statistical procedure was to determine, for each person involved, a period of risk. In the absence o f any episode of the illness in question before July 1, 1957, the risk period starts on that date; however, if such a previous episode has occurred, no risk period exists at all. Then the period, if any. lasts until July 1. 1972,
46
death or onset o f illness, whichever occurs first. Note that the start of an episode once and for all terminates the risk period (as vascular dementia must be regarded as a chronic disease). The risk period is then divided into segments, a new' segment beginning when the per son enters a new 10-year age group. Finally the results are aggregated over the entire cohort, i.e. for every age group the lengths of all risk period segments in the age group are added together. I n the same way the number of first episodes of vascular dementia is counted for each age group. During both these aggregation procedures the two sexes are treated separately. The reader interested in statistics is referred to Rorsman et al. [ 18] for further details of the method used.
Results
The incidence and risk of contracting vascular demen tia based on data from a total population, the Lundby 1957 cohort, during the period 1957-1972. arc given in tables 5-7. 58 probands developed vascular dementia during the 15-year period. The distribution of ages, sexes, and degrees of impairment of the illness are given in the tables. When all the degrees of impairment were taken together, considerably more men than women developed vascular dementia. Only the severe form showed no dif ferences between the sexes.
Hagnell/Franck/Gräsbeck/Öhman/Öjesjö/ Otterbeck/Rorsman
Vascular Dementia in the Lundby Study
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According to her daughter she was the type of person who never complained. When her husband died, she took it with composure. She left her home and moved to her daughter in another town. Later she had an attack of herpes zoster involving the left side of her face and the inside of her mouth and ear and, according to her daughter, she never really was herself after that. She was tired and feeble and had difficul ties in walking, largely because of arthritis in her knees. For many years she had been occasionally absent-minded, seeming completely lost to her surroundings for about ten minutes before returning to nor mal. She became more and more forgetful. For example, she did not always remember that her husband was dead. She became increasingly taciturn and could not control her bladder and bowel. At the age of 74 she had a cerebral thrombosis and was admitted to hospital with right-sided hemiplegia including the facial nerve. She was somnolent and had difficulties in articulating. She was treated with corticosteroids and physiotherapy but made only moderate improvement and was merely able to sit beside her bed during the daytime. She answered when she was spoken to but was not fully oriented in her mind. Evaluation. Lundby: vascular dementia, medium impairment. Corresponding to ICD-9 290.4 and DSM-III-R 290.40
Table 6. The incidence and risk of contracting severe and medium vascular dementias during the 15-year period
1957-1972 Age group years
Men
0-49 50-59 60-69 70-79 80-89 90-99 100+
Total
Women
0-49 50-59 60-69 70-79 80-89 90-99 100+
Total
Observation years under risk
Cases
Rate per year
Probability of disease during age interval
Cumulative probability of disease
0.000 (0.000) 0.007 (0.005) 0.045(0.014) 0.053(0.021) 0.225 (0.060)
0.000 (0.000) 0.007 (0.005) 0.051 (0.015) 0.102(0.024) 0.304(0.057)
-
-
-
-
11,490.5 3.002.7 2,168.9 1.095.9 432.1 62.9 0
0 2 10 6 11 3 0
0.0000 (0.0000) 0.0007 (0.0005) 0.0046(0.0015) 0.0055 (0.0022) 0.0255 (0.0077) 0.0477(0.0275) 0.0000 (0.0000)
18,253.0
32
0.0012(0.0002)
-
-
10.848.5 2.686.6 2.267.8 1.330.0 517.9 66.8 2.6
0 0 1 14 5 0 0
0.0000 (0.0000) 0.0000 (0.0000) 0.0004 (0.0004) 0.0105 (0.0028) 0.0097 (0.0043) 0.0000(0.0000) 0.0000 (0.0000)
0.000 (0.000) 0.000 (0.000) 0.004 (0.004) 0.100(0.025) 0.092 (0.039)
0.000 (0.000) 0.000 (0.000) 0.004 (0.004) 0.104(0.026) 0.186(0.042)
-
-
-
-
17.720.2
20
0.0009 (0.0002)
-
-
Values in parentheses are SE.
Table 7. The incidence and risk of contracting severe, medium and mild vascular dementias during the 15-year period 1957-1972
Age group years
Men
0-49 50-59 60-69 70-79 80-89 90-99 100+
Total
Women
Total
0-49 50-59 60-69 70-79 80-89 90-99 100+
Observation years under risk
Cases
Rate per year
Probability of disease during age interval
Cumulative probability of disease
0.000 (0.000) 0.007(0.005) 0.054(0.015) 0.054(0.021) 0.263(0.062)
0.000(0.000) 0.007 (0.005) 0.060 (0.016) 0.111 (0.025) 0.345 (0.058)
-
-
-
-
11.490.5 3,002.7 2.166.4 1,089.2 425.5 62.9 0
0 2 12 6 13 3 0
0.0000(0.0000) 0.0007 (0.0005) 0.0055(0.0016) 0.0055 (0.0022) 0.0306 (0.0085) 0.0477(0.0275) 0.0000 (0.0000)
18,237.2
36
0.0013(0.0002)
-
-
10,848.5 2.686.6 2,261.0 1.329.0 512.5 63.8 2.6
0 0 3 14 5 0 0
0.0000 (0.0000) 0.0000(0.0000) 0.0013(0.0008) 0.0105(0.0028) 0.0098 (0.0044) 0.0000(0.0000) 0.0000(0.0000)
0.000 (0.000) 0.000 (0.000) 0.013(0.008) 0.100 (0.025) 0.093 (0.040)
0.000 (0.000) 0.000 (0.000) 0.013(0.008) 0.112(0.026) 0.194 (0.042)
-
-
-
-
17,704.0
22
0.0010(0.0002)
-
-
47
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Values in parentheses are SE.
Discussion
Over a long period of time the aged individuals have formed a rapidly increasing segment of the population of the developed countries. A similar change is in progress in most developing countries [ 19], In the Lundby study, vas cular dementia is by far the most common mental illness in men > 60 years of age. the incidence rate being 9 .1 per 1,000 person years, while in women in the same age groups depression clearly dominates with an incidence rate of 8.2 per 1.000 person years. SDAT is the second most common disease in both men and women among the elderly in this population, the incidence rate being 5.0 and 5.5 per 1,000 person years, respectively. A good many of the men develop vascular dementia as early as their sixties, while women are more often affected in their seventies. In the age range 80-89. men again dom inate (table 7). Looking at the cumulative risk up to age 90 of developing vascular dementia one finds that the male predominance is evident, but only when the less severe types are considered. When the same Lundby cohort was investigated with regard to the incidence of SDAT [10], no sex difference was found. However, combined data from community surveys show a tendency towards a female predominance in SDAT and a male one in vascular dementia [20]. Hence, prevalence data from the EURODEM research programme point towards a male dominance of vascular dementia, except for the age group of 80-89, where the Lundby study and a Finnish one showed a female pre dominance. While the 1957 Lundby prevalence data showed a slight weighting towards men. the correspond ing 1972 data changed into a weighting towards women in this age group because of a steeper decrease in men
than in women. The question has been raised whether this was due to a true increase in incidence [12]. The preva lence data referred to do not. contrary to our incidence figures, take into account the events that occurred during the 15-year period, such as deaths. There are certain find ings indicating that men develop their dementia and die earlier than women [21]. This would to a certain extent explain the high prevalence and incidence found among the old women [ 12]. The provision of medical and social welfare for the aged individual has become a matter of great concern for all society. The question has not only large economic implications, it should also be seen against a background of social structure, where the multiple generation family is no longer a way of life. Social reforms and medical inter vention, however, have aimed at preventing impairment among the elderly and providing alternatives in care. Lon gitudinal population studies, based on incidence data, will best reflect the results of such efforts. Incidence data give more reliable information about changes over time and differences between the sexes, and we are now col lecting data for an incidence study up to 1992. Finding relevant background factors, the topic of the succeeding article, could in turn provide opportunities for pre vention.
Acknowledgements Our sincere thanks to J. Lanke for the statistical work, and to R.G. Dewsnap for revising the manuscript. This study was supported by the follow ing grants: the Bank of Sweden Tercentenary Founda tion No. 71/2; the Swedish Medical Research Council No. 3474. 4803. 6008,6881: the Swedish Ministry of Health and Social Affairs. Delegation for Social Research No. 83/64: 1-2.
References
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