Incidence of and risk factors for type-2 diabetes in a general population: The Tromsø Study

• Published in: Scandinavian Journal of Public Health
• Main Authors: Joseph, Josepha, Svartberg, Johan, Njølstad, Inger, Schirmer, Henrik
• Format: Article in Journal/Newspaper
• Language: English
• Published: SAGE Publications 2010
• Subjects: Tromsø
• Online Access: http://dx.doi.org/10.1177/1403494810380299; http://journals.sagepub.com/doi/pdf/10.1177/1403494810380299

Aims: To determine the gender-specific incidence and risk factors of type-2 diabetes mellitus (T2DM) in a general population. Methods: The study is based on 12,431 men and 13,737 women aged 25-98 years, attending the Tromsø Study in 1994 and followed through 2005, who did not have diabetes when entering the study. Sex-specific hazard ratios were estimated from Cox proportional hazard models. Results: A total of 522 cases of T2DM were registered, 308 among men and 214 among women. The age-standardised incidence rate was higher in men than in women, 2.6 (95% CI 2.32—2.90) and 1.6 (95% CI 1.40—1.83) per 1000 person-years, respectively. In multivariate survival analysis, age, body mass index (BMI), triglycerides, high-density lipoprotein (HDL) cholesterol, hypertension, family history of diabetes, low education and smoking were independent predictors of T2DM in both genders (p>0.05). Total cholesterol and lack of leisure-time physical activity were independent predictors in men only. We found an interaction between HDL cholesterol and triglyceride levels (p>0.001) and between triglyceride levels and a positive family history of diabetes (p = 0.04). These interactions were independent of BMI. A positive family history combined with triglycerides in the highest tertile and BMI >25 kg/m 2 conveyed a 10-year risk of T2DM of 10% (95% CI 8—12%) vs. 0.2% (95% CI 0.08—0.31%) for the lowest risk group. Conclusions: A family history of diabetes, elevated BMI, and high triglyceride levels identifies independent of cardiovascular risk factors, a group with especially high risk of T2DM.