The association of diabetes and BMI among Melanesian and Indian Fijians aged ≥40 years

Abstract

The present study examines the association of diabetes with BMI (kg/m 2) in Asian-Indian and Melanesian Fijian populations sharing a common environment. A population-based survey was used to investigate the risk of diabetes (defined by glycosylated Hb concentration 65% among participants who denied previous diagnosis of the disease by a medical practitioner) by sex, ethnicity and strata of BMI in a series of age-adjusted logistic regression models. Ethnicity and BMI interactions were compared using WHO and empirically derived BMI cut-off points. Indians had a greater risk (BMI and age adjusted) of undetected diabetes than Melanesians in both males (OR 299, 95% CI 173, 517; P<0001) and females (OR 226, 95% CI 156, 328; P<0001). BMI 25 to <30 and 30kg/m2 conferred a higher risk of diabetes compared with a BMI 185 to <25kg/m2. Risk was higher for males with a BMI 25 to <30kg/m2 (OR 235, 95% CI 124, 446; P=0007) and BMI 30kg/m 2 (OR 608, 95% CI 306, 1207; P<0001) than for females with the same BMI (OR 185, 95% CI 111, 308; P=0027 and OR 210, 95% CI 128, 344; P=0002, respectively). However, the threshold that appeared to differentiate higher risk varied by ethnicity and sex. For Melanesians, BMI thresholds suggested were 25kg/m2 for males and 32kg/m2 for females. For Indo-Fijians, these were 24 and 22kg/m2 for males and females, respectively. Disaggregating by ethnicity and sex, and applying specific evidence-based thresholds, may render BMI a more discriminating tool for assessing the risk of developing diabetes among Fiji adults. © 2011 The Authors.