Abstract P057: Optimal Modifiable Lifestyle Risk Factor Scores Are Associated with Lower Risk of Type 2 Diabetes Mellitus in African Americans - The Jackson Heart Study

Abstract

Background: The associations of combined modifiable risk factors for incident diabetes (physical activity, television watching, dietary intake, sleep disordered breathing and smoking) are less well investigated in African Americans (AAs). Hypothesis: We hypothesized that an optimal modifiable lifestyle risk factor score would be inversely associated with incident diabetes among AAs. Design and Methods: Data on modifiable risk factors was collected by questionnaire at baseline (2000-2004) in a population-based sample of AAs in the Jackson Heart Study. Incident diabetes (fasting glucose ≥126 mg/dl, physician diagnosis, use of diabetes drugs, or HbA1c ≥ 6.5%) was assessed over 12 years, among adults without prevalent diabetes at baseline. Participants were excluded for missing data on baseline covariates or diabetes follow-up. Incidence rate ratios (IRR) were estimated using Poisson regression modeling adjusting for age, sex, education, current occupation status, systolic blood pressure and body-mass index. Modifiable lifestyle factors (regular exercise, healthy diet, smoking avoidance, lower amounts of television watching and low sleep disordered breathing burden) were combined in risk score categories of poor (0-3 points), average (4-7 points), optimal (8-11 points). Results: Among 3,252 adults (mean age 53.3 years, 64% female) there were 560 incident diabetes cases (median follow-up 7.6 years). An average or optimal compared to a poor modifiable lifestyle risk score was associated with a 21% (IRR 0.79, 95% CI: 0.62, 0.99) and 31% (IRR 0.69, 95% CI: 0.48, 1.01) lower risk of diabetes, respectively, in a monotonic fashion (p=0.03). Body-mass index (BMI) and glycemic status at baseline modified the association of lifestyle risk score with diabetes - among participants with BMI < 30 kg/m 2 , IRRs for average or optimal compared to poor categories were 0.60 (95% CI: 0.40, 0.91) and 0.53 (95% CI: 0.29, 0.97), respectively, compared to 0.90 (95% CI 0.67, 1.21) and 0.83 (95% CI: 0.51, 1.34) among participants with BMI ≥ 30 kg/m 2 . For participants with normoglycemia (normal fasting glucose and HbA1c) at baseline, the IRRs for average or optimal compared to poor categories were 0.64 (95% CI: 0.43, 0.96) and 0.57 (95% CI: 0.31, 1.04), respectively, compared to 0.90 (95% CI 0.69, 1.19) and 0.80 (95% CI: 0.52, 1.23) among participants with prediabetes at baseline. Conclusions: Modifiable lifestyle factors are associated with a lower risk of diabetes among AAs, with greater effects among those with lower adiposity and normoglycemia. Lifestyle interventions to reduce obesity have focused on individuals with high BMI and/or prediabetes (high risk approach). Our study suggests that AAs at the lower end of the diabetes risk spectrum may derive significant long-term benefit from diabetes prevention strategies focused on the outlined modifiable lifestyle risk factors.