Arturo Zarate, MD

Diabetes Mellitus in Mexico

Diabetes in Mexico is a public health problem with considerable medical, social, and economic consequences. Although detailed data on the prevalence of diabetes and its complications are not available, health services utilization data of the Social Security organization (Instituto Mexicano del Seguro Social) indicate increasing use of primary and tertiary care for diabetes over a recent 10-yr period. A health interview survey conducted in 1988 indicated that, in different areas, from 3.5 to 12.7% of people aged 2:65 yr are believed to have diabetes, and that rates are higher in many of the states bordering the United States. Diabetes ranks among the leading 10 causes of death throughout the country. Although the ranking varies from state to state and the diagnosis may not appear on the death certificate when death results from a complication of the disease, in 1983 diabetes was the leading cause of death in Mexico and the first or second leading cause in many of the states bordering the U.S. Gestational diabetes contributes to perinatal mortality, and in view of the high birth rates, represents an important facet of the disease in Mexico. The impact of specific complications of diabetes on morbidity and mortality in Mexico are not well delineated. The relative frequency and impact of insulin-dependent and non-insulin-dependent diabetes in Mexico are not known. Diabetes Care 14 (Suppl. 3): 672-75, 1991

iabetes mellitus is a public health problem affecting countries regardless of their level of development, moreover, the disease has multiple medical, social, and economic repercussions. Although numerous studies on the prevalence of diabetes mellitus have been conducted in Latin America, they are not comparable because different criteria were used and the samples were not representative. In Latin

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America, the prevalence of diabetes has been estimated to be between 2 and 12%; in Mexico, it is between 2 and 3%. The morbidity due to diabetes is not known because records are often inadequate; nevertheless, some information is available on hospital discharges and outpatient charts. However, the morbidity records vary in quality and completeness, and the data obtained from them only reveal part of the problem.

MORTALITY For the past several years in Mexico, diabetes mellitus has been listed among the 10 leading causes of death. The mortality rate was 8/100,000 inhabitants in 1960 and 22.9/100,000 in 1982. However, there is a lack of uniformity in the certification of cause of death, and frequently deaths among diabetic subjects are categorized as due to cardiovascular complications without mention of diabetes on the certificate (1). In 1983, the geographic distribution of mortality attributed to diabetes was studied. In addition to observing that the rates were not uniform throughout the country, the study showed that diabetes was among the 10 leading causes of death in all states. Diabetes was the leading cause of death in Mexico City and the leading or second cause in many states that border the United States. Between 1978 and 1983, the mortality attributed to diabetes mellitus in relation to age was examined (Table 1). As expected, the rates are much higher in From the Endocrine Research Unit, Mexican Institute of the Social Security, Mexico, D.F., Mexico. Address correspondence and reprint requests to Arturo Zarate, MD, Unidad de Investigacion en Enfermedades Endocrinas, Apartado Postal 107-115 06760, Mexico, D.F., Mexico.

DIABETES CARE, VOL. 14, NO. 7, SUPPL. 3, JULY 1991

A. ZARATE

TABLE 3 National survey of health (February 1988) prevalence/100 people of subjects believed to have diabetes mellitus

TABLE 1 Mortality due to diabetes mellitus (1978-1983) Age (yr)

Age (yr) Yr

1-4

5-14

15-24

25-44

45-64

>65

Total

1978 1979 1980 1981 1982 1983

0.2 0.1 0.2 0.2 0.2 0.3

0.2 0.2 0.2 0.3 0.2 0.2

0.9 0.9 0.9 0.7 0.8 0.9

5.7 6.1 6.2 6.0 5.8 6.3

69.2 73.7 75.5 78.9 83.5 89.5

308.7 330.6 352.5 358.2 381.3 421.3

18.7 19.9 21.0 21.6 23.0 25.3

Rates per 100,000 people. Based on material from the Secretary of Planning and Budget, Mexican Institute of Social Security.

those aged ^45 yr. There appears to be a trend of increasing rates over time among people aged ^45 yr, and as in other countries, the rates are highest in people aged ^65 yr. In the same study, the proportion of deaths was greater in women than men at all ages (Table 2). In 1988, a national health interview survey was conducted to determine the prevalence of the principal diseases in Mexico. Table 3 shows the prevalence of diabetes mellitus, as determined by the home questionnaire, in samples of the general population. Higher prevalences of diabetes mellitus were found in Baja California, Coahuila, and Chihuahua, which border the U.S., than elsewhere.

DATA FROM MEXICAN INSTITUTE OF SOCIAL SECURITY (IMSS) Since 1980, the IMSS has had an information system that can determine the number of consultations in the three levels of medical care in the IMSS health-care system. In 1980, there were 433,148 consultations for diabetes at the primary-care level; this number has increased progressively in subsequent years reaching 1,529,307 in 1985 (Fig. 1). However, these figures include both first time consultations and follow-up visits for diabetes and probably reflect an increasing preva-

Aguascalientes Baja California Chihuahua Colima Coahuila Mexico City Guanajuato Nayarit Zacatecas

24-34

45-54

65

1.4 0.4 0.3 0.1 0.7 0.2 0.0 1.0 0.7

7.3 6.7 3.1 4.6 6.4 11.3 4.3 5.0 2.8

3.5 12.7 10.4 6.0 11.2 7.6 4.7 9.1 4.8

Based on ref. 4.

lence of the disease. From 1983 to 1985, diabetes ranked fifth among the 10 principal reasons for consultation and was only surpassed by acute respiratory infections, intestinal infections, arterial hypertension, and parasitosis. In the tertiary-care hospitals in 1980 and 1981, there were >50,000 consultations each year for diabetes; this increased to 152,000 in 1984 (Fig. 2). The number of consultations increased almost threefold, whereas the population covered by IMSS did not change. Thus, these data showed a real increase in the prevalence of diabetes and its complications. Furthermore, 1 of 17 diabetic subjects was attending a clinic in the highly specialized hospital units. Since 1976, the causes of death in IMSS hospitals have been recorded. In that year there were 1419 deaths attributed to diabetes, whereas in 1984 there were 6070 (Fig. 3). Thus, from 1976 to 1984, the number of deaths attributed to diabetes quadrupled. In 1984, diabetes was the leading cause of death in the population covered by the IMSS. This means that diabetes surpassed cirrhosis, intestinal infections, respiratory diseases, and myocardial infarction as a cause of death. 2 000 000-

1529 307

V> I 500000~ I "" I

TABLE 2 Number and percentage of deaths due to diabetes mellitus according to sex (1976-1981)

n

1976 1977 1978 1979 1980 1981

5156 5170 5457 6405 6507 6889

Total number of deaths

n 44 44 44 47.5 44.5 45

6563 6531 6828 7084 8119 8441

56 56 56 52.5 55.5 55

DIABETES CARE, VOL. 14, N O . 7, SUPPL. 3, JULY 1991

11,719 11,701 12,285 13,489 14,727 15,330

89744

[~I~ [ - I" " I "* I

800 000-

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Women

Men Yr

865 868

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1

"I —I [ ~ I~ "I ~I [ ~ I~

* I "* I '

[ " I~ ~ I "" I ' [ ~ I~ " I ~I IHTFT

82 YE

AR

FIG. 1. Number of consultations for diabetes in primary health-care units. From Garrido (1).

673

DIABETES MELLITUS IN MEXICO

160 000 H

152 419

2 000000-

130635

o u

3 000 000-

120 000-

O

1000 00080 000-

UJ

75 283

•

52 798 40 000-

z

80

56 501

81

500 000-

83

82

84

YEAR

100 000-

FIG. 2. Consultations for diabetes mellitus in tertiary-care hospitals almost tripled but population covered by Mexican Institute of Social Security did not, indicating a real increase in diabetes and its complications.

In 1969, a program for the detection of diabetes mellitus was started in Mexico; 46,540 cases were found and this figure increased every year until it reached 3,064,457 in 1983. Because the IMSS serves - 1 8 million people >25 yr of age, the annual incidence of newly detected diabetes is considerable (Fig. 4).

50 000

-

10 000

-

69

71

73

75

77

79

81

83

85

Y E A R FIG. 4. Number of new cases of diabetes as determined by Mexican Institute of Social Security program for early detection of diabetes. From Garrido (1).

DIABETES AND PREGNANCY Gestational diabetes occurs during pregnancy in women who are obese, and its incidence increases with age. Many women who develop carbohydrate intolerance in pregnancy develop diabetes after childbirth. Gestational diabetes is a serious problem because it influences perinatal mortality. The most frequently observed complications of gestational diabetes are preeclampsia, macrosomia, hydramnios, and congenital malformations. What is also striking is the direct relation between

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TABLE 4 Perinatal mortality in diabetic mothers in tertiary-care hospitals 82

83

84

FIG. 3. From 1976 to 1984, mortality (per 1000 hospitalized patients) due to diabetes mellitus in population covered by Mexican Institute of Social Security quadrupled.

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mortality and the weight of the pregnant women; the greater the obesity, the greater the prevalence of morbidity and mortality (2,5). In Mexico, women are generally referred to specialized centers when they are 25-30 wk pregnant (6). In these centers, perinatal mortality rates in women with gestational diabetes were ~ 6 of 1000 live births (Table 4). However, when care is initiated only when pregnancy is advanced the outcome is much worse (Table 5). These data (3,4) emphasize the importance of monitoring for diabetes during pregnancy in the primary-care setting (5,6). Many women with gestational diabetes in Mexico are subsequently found to have impaired glucose tolerance or non-insulin-dependent diabetes mellitus when tested in the postpartum period (Table 6). Among women with gestational diabetes, the prevalence of diabetes mellitus after delivery was lower in Monterrey and Mexico than in San Luis Potosi.

Mexico City North area South area Monterrey

6.2* 5.9 5.6

"Per 1000 live births.

DIABETES CARE, VOL. 14, NO. 7, SUPPL. 3, JULY 1991

A. ZARATE

TABLE 5 Perinatal mortality in diabetic mothers who were referred for specialized metabolic control late in gestation

Mexico City Monterrey Merida

Percent of admissions

Perinatal mortality (%)

58 67 72

31.2 36.0 42.5

CONCLUSIONS

Despite attempts to determine the prevalence of diabetes mellitus in Mexico, available data do not reflect the rates or impact of the disease in the general population; continued efforts to determine the impact of diabetes on health care are needed. Non-insulin-dependent diabetes, usually associated with obesity, is the predominant type of diabetes in the country. Some statistical data indicate that diabetes is probably more prevalent in the states that border the U.S. (e.g., Nuevo Leon, Sonora, Chihuahua, and Baja California). Efforts are being made to determine the predominant complications of diabetes. There are indications that the frequent complications include blindness and amputations due to peripheral vascular insufficiency. Because the birth rate is high in Mexico, gestational diabetes is common. Widespread screening for diabetes in pregnant women would potentially result in lower perinatal morbidity and mortality and reduce the cost of care for high-

TABLE 6 Results of oral glucose tolerance testing after delivery in patients with gestational diabetes

Mexico Monterrey San Luis Potosi

Impaired glucose tolerance (%)

Non-insulin-dependent diabetes (%)

15.7 19.2 20.0

12.0 11.5 21.2

DIABETES CARE, V O L . 14, N O . 7, SUPPL. 3, JULY 1991

risk pregnancies associated with the delayed diagnosis of diabetes. Studies are necessary to establish the prevalence of diabetes in Mexico and the distribution of morbidity and mortality by age-group, weight, and duration of the disease. Genetic factors that determine the association of obesity and diabetes should be investigated. It is believed that the type of diet, in particular the type of carbohydrates and the amount of fiber, can influence the onset of diabetes mellitus. Mexican immigrants to the U.S. have a high prevalence of diabetes and this may be related to the process of adapting to another culture. Future studies in Mexico should initially focus on 7) prevalence, 2) knowledge of the risk factors, 3) studies on the demand of health services and cost-benefit analysis of medical care, and 4) frequency of both insulin-dependent and non-insulin-dependent diabetes.

ACKNOWLEDGMENTS This study was partially funded with a grant from the National Council of Science and Technology (PSCABNA-021542), Mexico City, Mexico.

REFERENCES 1. Garrido M: Deteccion y Control de la Diabetes Mellitus. Mexico City, Mexico, Institute Mexicano del Seguro Social, 1987 2. Forsbach G, Contreras-Soto JJ, Fong G, Flores G, Moreno O: Prevalence of gestational diabetes and macrosomic newborns in a Mexican population. Diabetes Care 11: 235-38,1988 3. Estadisticas Vitales. Mexico, Unidad de Planeacion de la Direccion General de Medicina Preventiva, Secretaria de Salud, 1987 4. Sepulveda J: Encuesta Nacional de Salud: Direccion General de Epidemiologia. Mexico, Secretaria de Salud, 1988 5. Zarate A, Canales EL, Niz J: Diabetes en la embarazada. Rev Med IMSS 24:167, 1986 6. Canales EL, Ablanedo J, Nava D, Cruz A, Zarate A: Complicaciones maternas y morbi-mortalidad perinatal en la diabetica tratada con hipoglucemiantes orales durante la gestacion. Arch Invest Med 18:241, 1987

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