Ethnicity and sex are strong determinants of diabetes in an urban Western society: implications for prevention

Aims/hypothesis: This study was conducted to investigate the prevalence of diabetes and its association with ethnicity and sex, to identify subgroups at special risk. Methods: We performed a population-based cross-sectional survey of 30- to 67-year-olds in an area of Oslo with low socio-economic status, and collected data using questionnaires, physical examinations and serum analyses for the 2,513 participants (attendance rate 49.3%). Results: In the age group 30-59 years, mean BMI was 28.5 (95% CI: 27.5-29.6) for South Asian women, 26.1 (25.9-26.4) for Western women, 26.7 (26.1-27.4) for South Asian men and 27.2 (26.9-27.5) for Western men. The diabetes prevalence rates were 27.5% (18.1-36.9) for South Asian women, 2.9% (1.9-3.4) for Western women, 14.3% (8.0-20.7) for South Asian men and 5.9% (4.2-7.5) for Western men. The age-adjusted odds ratio (OR) for diabetes for women vs men was 1.9 (0.9-4.1) for South Asians, and 0.4 (0.3-0.6) for the Western population (p < 0.001). The age-adjusted OR for diabetes for South Asians vs Westerners was 11.0 (5.8-21.1) for women and 3.0 (1.6-5.4) for men, and after adjustment for WHR the ORs were 7.7 (3.9-15.3) for women and 2.6 (1.4-4.9) for men. After additional adjustments for physical activity, education, body height and fertility for women, the OR was 6.0 (2.3-15.4) for women and 1.9 (0.9-4.0) for men. Conclusions/interpretation: The alarmingly high prevalence of diabetes among South Asian women in Norway needs further investigation, as it has considerable public health implications. Ethnic differences in OR for diabetes persisted after adjustment for age, adiposity, physical activity and education. These differences were still present for women after additional adjustment for body height and fertility.