(OR12-02-24) Proportion of Major Chronic Disease Attributable to Poor Quality Diet and Inadequate Physical Activity in the United States, Independent of Adult Body Weight

Objectives: The distinct effects of lifestyle intervention independent of adiposity are not well quantified. We estimated the proportion and number of incident chronic disease cases in the United States (US) attributable to poor quality diet and inadequate physical activity, before and after accounting for body weight change.

Methods: We followed 199,814 individuals in the Nurses’ Health Study, Nurses’ Health Study II, and Health Professionals Follow-up Study who provided diet and lifestyle data via biennial questionnaires. Diet quality was evaluated using the Alternative Healthy Eating Index 2010 (AHEI, modified to exclude alcohol and trans fat components) and physical activity was defined as total metabolic equivalent of task (MET)-hours of recreational activity per week. New diagnoses of type 2 diabetes, cardiovascular disease (CVD), and cancer were self-reported and confirmed via supplemental questionnaire or medical record. Multivariable-adjusted pooled logistic regression estimated risk ratios by joint effect of diet quality and physical activity, first independent of baseline BMI and then additionally independent of change in body weight over follow-up. Population attributable fractions (PAFs) were estimated using risk factor distribution and case incidence.

Results: We documented 64,181 chronic disease cases over 3.7 million person-years of follow-up (16,667 type 2 diabetes, 16,240 CVD, 31,274 cancer). The combination of high dietary quality (AHEI score >50 vs. < 30) and physical activity ( >28 vs. < 7 MET-hours/week) was associated with 23% lower risk of chronic disease in multivariable models (95%CI 18–38%); this estimate was reduced to 17% after adjustment for change in body weight (95%CI 12–32%). Associations varied substantially by outcome, ranging from 0.50 (95%CI 0.44–0.56) for diabetes to 0.99 for cancer (95%CI 0.91–1.08). In the US, 18% (95%CI 5–26%) of chronic disease was attributable to poor quality diet and low physical activity, and 13% (95%CI 0–23%) of chronic disease was attributable to poor quality diet and low physical activity independent of effects on body weight.

Conclusions: A significant fraction of US chronic disease was attributable to poor quality diet and inadequate physical activity in adulthood, independent of starting BMI and weight change.

Funding Sources: This work was supported by National Institutes of Health grants.