A Cross-Sectional Epidemiology Study of the Relationships between Body Mass Index and the Risk of Diabetes, and Diabetes and the QRISK2 10-Year Cardiovascular Risk Score Using India Heart Watch Data

Abstract

Background: Among Asian Indians worldwide, the prevalence of diabetes is high, although the literature suggests a gap in understanding the risk of T2DM, and the association between BMI and T2DM in Asian Indian populations. In addition, the risk for developing CVD utilizing a risk calculator like QRISK2 has not been evaluated with data from the Indian sub-continent. For Asian Indians, the guidelines for therapeutic interventions and prevention strategies are not based on ethnic-specific data, allowing questionable applicability of guidelines developed in the West to these populations.

Objective: The purpose of this study was to examine the effect of National Institute of Health and Clinical Excellence and American Diabetes Association consensus adjusted BMI on the risk of T2DM in a representative sample of ~ 6,000 Asian Indians to narrow the knowledge gap and achieve population specificity. The study also evaluated the 10-year risk of developing CVD using the QRISK2 algorithm to generate valid, population-specific, CVD risk scores.

Design: A quantitative, epidemiologic, cross-sectional design was selected to investigate the risk relationship between BMI (per consensus) and T2DM, and quantify the impact of T2DM on the QRISK2 10-year risk of developing CVD using Indian Heart Watch study data.

Results: A Mantel–Haenszel test showed that a one unit increase in BMI significantly increased the odds of T2DM, MH χ²(1) = 51.48, OR = 1.28, 95% CI [1.19, 1.37], p < .0001. Multivariate binary logistic regression showed that BMI significantly increased the odds of T2DM in the four highest categories: (BMI > 18.5 to 23.0, OR = 1.76, p = .040); (BMI > 23.0 to 27.5, OR = 2.11, p = .006); (BMI > 27.5 to 30.0, OR = 2.24, p = .004); and (BMI > 30, OR = 3.49, p < .001). A Wilcoxon rank-sum test demonstrated a statistically significant difference in median QRISK2 10-year risk scores (Δ Mdn = 13.3) between subjects without T2DM (Mdn = 4.9, n = 4,345) and those with T2DM (Mdn = 18.2, n = 925), z = -26.425, p < .0001. Multivariate negative binomial regression revealed that T2DM significantly increased the QRISK2 10-year risk score by (+ 77.7%), IRR = 1.78, 95% CI [1.72, 1.84], z = 33.99, p < .001. The two highest BMI categories (> 27.5 to 30.0) and (> 30.0) significantly increased the QRISK2 10-year score by 19.2% and 22.3%, respectively, and each covariate also significantly increased QRISK2 10-year score. Conclusion: This investigation provides valid estimates of the risk of T2DM resulting from BMI and represents the first use of QRISK2 to generate ethnicity-specific, 10-year CVD risk scores. The findings may serve as a catalyst in the T2DM and CVD therapeutic arena for advancing prevention, therapeutic decisions, and interventions for Asian Indians. Importantly, the results quantified the hypothesis of small anecdotal publications: Asian Indians have a higher risk and burden of T2DM and CVD, starting earlier in age and at lower BMI values than in western Caucasian populations. The implications have widespread public health relevance and clinical utility to advance preventative healthcare among Asian Indians. Keywords: Cardiovascular disease, risk score, QRISK2, Framingham Heart Study, FRS-CHD, FRS-CVD, body mass index, type-2 diabetes, India Heart Watch