diabetes research and clinical practice 106 (2014) e34–e37
Contents available at ScienceDirect
Diabetes Research and Clinical Practice jou rnal hom ep ag e: w ww.e l s e v i er . c om/ loca te / d i ab r es
Brief report
The healthy Nordic diet and incidence of Type 2 Diabetes — 10-year follow-up N. Kanerva a,b,*, H. Rissanen c, P. Knekt c, A.S. Havulinna a, J.G. Eriksson a,d,e,f, S. Ma¨nnisto¨ a a
Department of Chronic Disease Prevention, National Institute for Health and Welfare, Helsinki, Finland Department of Public Health, University of Helsinki, Helsinki, Finland c Department of Health, Functional Capacity and Welfare, National Institute for Health and Welfare, Helsinki, Finland d University of Helsinki, Department of General Practice and Primary Health Care, Helsinki, Finland e Helsinki University Central Hospital, Unit of General Practice, Helsinki, Finland f Folkha¨lsan Research Center, Helsinki, Finland b
article info
abstract
Article history:
Studies have shown that a diet of healthy foods typical of Nordic countries has a beneficial
Received 16 May 2014
effect on risk factors for Type 2 Diabetes (T2D), such as obesity and low-grade inflammation.
Accepted 23 August 2014
However, longitudinal epidemiological studies examining the association between the
Available online 3 September 2014
healthy Nordic diet and T2D are lacking. # 2014 Elsevier Ireland Ltd. All rights reserved.
Keywords: Nordic diet Dietary score Diabetes
1.
Introduction
Researchers have estimated that 91% of diabetes cases can be attributed to modifiable lifestyle factors, such as physical activity, smoking, and diet [1]. For example, the Mediterranean diet is found to associate with lower Type 2 Diabetes (T2D) risk [2,3]. For some populations, adoption of the Mediterranean diet is not perhaps culturally or ecologically optimal. In Scandinavia, a diet rich in Nordic fruits and berries, roots and vegetables, rye, low-fat dairy products, and fish has been suggested as a culturally suitable choice for the Mediterranean diet [4]. Thus far, clinical and cross-sectional findings suggest that the Nordic diet can improve body weight and inflammation,
which are strong predictors for T2D development [5–8]. This study aimed to examine whether the healthy Nordic diet associates with T2D incidence during 10 years of follow-up.
2.
Methods
This prospective study included the clinical part of the Helsinki Birth Cohort Study (HBCS) (n = 2003) conducted during 2001–2002 [9] and the Health 2000 Survey (Health 2000) (n = 8028) [10] conducted during 2000–2001. Participants who acceptably filled in the food frequency questionnaire (FFQ) and were free of diabetes at baseline were included (HBCS n = 1822, Health 2000 n = 4923).
* Corresponding author at: Department of Chronic Disease Prevention, National Institute for Health and Welfare, P.O. Box 30, FI-00271 Helsinki, Finland. Tel.: +358 408272356; fax: +358 295248338. E-mail address: [email protected] (N. Kanerva). http://dx.doi.org/10.1016/j.diabres.2014.08.016 0168-8227/# 2014 Elsevier Ireland Ltd. All rights reserved.
e35
diabetes research and clinical practice 106 (2014) e34–e37
Statistical analyses were performed with SAS version 9.2 (SAS Institute, Cary, NC, USA) and R statistical software version 2.15.1 [14]. Logistic regression was used to estimate study-specific relative hazard ratios (HR) and two-sided 95% confidence intervals (CI) for T2D by quintiles of the BSDS. These estimates were combined, using the random-effects meta-analysis [15]. Interaction analysis included stratifying participants according to their metabolic health status (HDL cholesterol, triglyceride and glucose concentration, and blood pressure) at baseline [16]. Sensitivity analyses were performed, excluding the first 2 years of follow-up; excluding under-reporters of energy intake; excluding participants with elevated fasting glucose (>5.6 mmol/l); and, in the HBCS, including only participants whose T2D status was confirmed with OGTT.
Both studies were conducted according to the guidelines in the Declaration of Helsinki and all procedures involving human subjects were approved by the Helsinki and Uusimaa Hospital District Ethics Committee. Diabetes cases were identified by linking the participants to the nationwide administrative registers on medication use (ATC codes beginning with A10) hospitalization and death (ICD-10 codes E10-E14) with a unique personal identification code assigned to each Finnish citizen. Whichever registered date was first was used as the date of first event. Participants’ habitual diet over the past year was measured, using a validated 128-item FFQ [11,12]. Adherence to the healthy Nordic diet was measured, calculating the Baltic Sea Diet Score (BSDS) [13]. The final score ranged from 0 to 25, higher scores indicating higher adherence to the diet. The studies assessed socioeconomic status and lifestyle factors with questionnaires; measured anthropometrics and blood pressure; drew blood; and in the HBCS, conducted a standard 75 g oral glucose tolerance test (OGTT). Research laboratories used automated clinical chemistry analysers and routine clinical chemistry methods to measure serum lipid fractions and fasting glucose concentration.
3.
Results
During the 10-year period, 541 T2D cases emerged (HBCS n = 183, Health 2000 n = 358). Participants’ characteristics are presented in Table 1. The pooled HR for T2D risk was lower in
Table 1 – Age- and sex-adjusted characteristics of the participants in the Health 2000 Survey and the HBCS. HBCS (n = 1822)
Characteristics
Health 2000 (n = 4923)
BSDS quintiles 1 Follow-up period Median follow-up time, y n Diabetes cases, n Age, y b Females, % c Years of education, y Excercise
Contents available at ScienceDirect
Diabetes Research and Clinical Practice jou rnal hom ep ag e: w ww.e l s e v i er . c om/ loca te / d i ab r es
Brief report
The healthy Nordic diet and incidence of Type 2 Diabetes — 10-year follow-up N. Kanerva a,b,*, H. Rissanen c, P. Knekt c, A.S. Havulinna a, J.G. Eriksson a,d,e,f, S. Ma¨nnisto¨ a a
Department of Chronic Disease Prevention, National Institute for Health and Welfare, Helsinki, Finland Department of Public Health, University of Helsinki, Helsinki, Finland c Department of Health, Functional Capacity and Welfare, National Institute for Health and Welfare, Helsinki, Finland d University of Helsinki, Department of General Practice and Primary Health Care, Helsinki, Finland e Helsinki University Central Hospital, Unit of General Practice, Helsinki, Finland f Folkha¨lsan Research Center, Helsinki, Finland b
article info
abstract
Article history:
Studies have shown that a diet of healthy foods typical of Nordic countries has a beneficial
Received 16 May 2014
effect on risk factors for Type 2 Diabetes (T2D), such as obesity and low-grade inflammation.
Accepted 23 August 2014
However, longitudinal epidemiological studies examining the association between the
Available online 3 September 2014
healthy Nordic diet and T2D are lacking. # 2014 Elsevier Ireland Ltd. All rights reserved.
Keywords: Nordic diet Dietary score Diabetes
1.
Introduction
Researchers have estimated that 91% of diabetes cases can be attributed to modifiable lifestyle factors, such as physical activity, smoking, and diet [1]. For example, the Mediterranean diet is found to associate with lower Type 2 Diabetes (T2D) risk [2,3]. For some populations, adoption of the Mediterranean diet is not perhaps culturally or ecologically optimal. In Scandinavia, a diet rich in Nordic fruits and berries, roots and vegetables, rye, low-fat dairy products, and fish has been suggested as a culturally suitable choice for the Mediterranean diet [4]. Thus far, clinical and cross-sectional findings suggest that the Nordic diet can improve body weight and inflammation,
which are strong predictors for T2D development [5–8]. This study aimed to examine whether the healthy Nordic diet associates with T2D incidence during 10 years of follow-up.
2.
Methods
This prospective study included the clinical part of the Helsinki Birth Cohort Study (HBCS) (n = 2003) conducted during 2001–2002 [9] and the Health 2000 Survey (Health 2000) (n = 8028) [10] conducted during 2000–2001. Participants who acceptably filled in the food frequency questionnaire (FFQ) and were free of diabetes at baseline were included (HBCS n = 1822, Health 2000 n = 4923).
* Corresponding author at: Department of Chronic Disease Prevention, National Institute for Health and Welfare, P.O. Box 30, FI-00271 Helsinki, Finland. Tel.: +358 408272356; fax: +358 295248338. E-mail address: [email protected] (N. Kanerva). http://dx.doi.org/10.1016/j.diabres.2014.08.016 0168-8227/# 2014 Elsevier Ireland Ltd. All rights reserved.
e35
diabetes research and clinical practice 106 (2014) e34–e37
Statistical analyses were performed with SAS version 9.2 (SAS Institute, Cary, NC, USA) and R statistical software version 2.15.1 [14]. Logistic regression was used to estimate study-specific relative hazard ratios (HR) and two-sided 95% confidence intervals (CI) for T2D by quintiles of the BSDS. These estimates were combined, using the random-effects meta-analysis [15]. Interaction analysis included stratifying participants according to their metabolic health status (HDL cholesterol, triglyceride and glucose concentration, and blood pressure) at baseline [16]. Sensitivity analyses were performed, excluding the first 2 years of follow-up; excluding under-reporters of energy intake; excluding participants with elevated fasting glucose (>5.6 mmol/l); and, in the HBCS, including only participants whose T2D status was confirmed with OGTT.
Both studies were conducted according to the guidelines in the Declaration of Helsinki and all procedures involving human subjects were approved by the Helsinki and Uusimaa Hospital District Ethics Committee. Diabetes cases were identified by linking the participants to the nationwide administrative registers on medication use (ATC codes beginning with A10) hospitalization and death (ICD-10 codes E10-E14) with a unique personal identification code assigned to each Finnish citizen. Whichever registered date was first was used as the date of first event. Participants’ habitual diet over the past year was measured, using a validated 128-item FFQ [11,12]. Adherence to the healthy Nordic diet was measured, calculating the Baltic Sea Diet Score (BSDS) [13]. The final score ranged from 0 to 25, higher scores indicating higher adherence to the diet. The studies assessed socioeconomic status and lifestyle factors with questionnaires; measured anthropometrics and blood pressure; drew blood; and in the HBCS, conducted a standard 75 g oral glucose tolerance test (OGTT). Research laboratories used automated clinical chemistry analysers and routine clinical chemistry methods to measure serum lipid fractions and fasting glucose concentration.
3.
Results
During the 10-year period, 541 T2D cases emerged (HBCS n = 183, Health 2000 n = 358). Participants’ characteristics are presented in Table 1. The pooled HR for T2D risk was lower in
Table 1 – Age- and sex-adjusted characteristics of the participants in the Health 2000 Survey and the HBCS. HBCS (n = 1822)
Characteristics
Health 2000 (n = 4923)
BSDS quintiles 1 Follow-up period Median follow-up time, y n Diabetes cases, n Age, y b Females, % c Years of education, y Excercise
