Incidence of and risk factors for type-2 diabetes in a general population: the Tromsø Study.
OBJECTIVE
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=.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. [corrected]
Joseph
Josepha
J
Department of Community Medicine, University of Tromsø, Tromsø, Norway. josepha.joseph@uit.no
Svartberg
Johan
J
Njølstad
Inger
I
Schirmer
Henrik
H
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000209:etiology; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology* / Q000209:etiology / Q000235:genetics; D015444:Exercise; D005260:Female; D005500:Follow-Up Studies; D020022:Genetic Predisposition to Disease; D006801:Humans; D015994:Incidence; D008019:Life Style; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D011446:Prospective Studies; D012307:Risk Factors; D014280:Triglycerides / Q000097:blood
D014280:Triglycerides