Greater Adherence to the Alternative Healthy Eating Index Is Associated with Lower Incidence of Physical Function Impairment in the Nurses' Health Study

Background: Physical function is integral to healthy aging, in particular as a core component of mobility and independent living in older adults, and is a strong predictor of mortality. Limited research has examined the role of diet, which may be an important strategy to prevent or delay a decline in physical function with aging. Objective: We prospectively examined the association between the Alternative Healthy Eating Index-2010 (AHEI-2010), a measure of diet quality, with incident impairment in physical function among 54,762 women from the Nurses' Health Study. Methods: Physical function was measured by the Medical Outcomes Short Form-36 (SF-36) physical function scale and was administered every 4 y from 1992 to 2008. Cumulative average diet was assessed using food frequency questionnaires, administered approximately every 4 y. We used multivariable Cox proportional hazards models to estimate the HRs of incident impairment of physical function. Results: Participants in higher quintiles of the AHEI-2010, indicating a healthier diet, were less likely to have incident physical impairment than were participants in lower quintiles (P-trend < 0.001). The multivariable-adjusted HR of physical impairment for those in the top compared with those in the bottom quintile of the AHEI-2010 was 0.87 (95% CI: 0.84, 0.90). For individual AHEI-2010 components, higher intake of vegetables (P-trend = 0.003) and fruits (P-trend = 0.02); lower intake of sugar sweetened beverages (P-trend < 0.001), trans fats (P-trend = 0.03), and sodium (P-trend < 0.001); and moderate alcohol intake (P-trend < 0.001) were each significantly associated with reduced rates of incident physical impairment. Among top contributors to the food components of the AHEI-2010, the strongest relations were found for increased intake of oranges, orange juice, apples and pears, romaine or leaf lettuce, and walnuts. However, associations with each component and with specific foods were generally weaker than the overall score, indicating that overall diet pattern is more important than individual parts. Conclusions: In this large cohort of older women, a healthier diet was associated with a lower risk of developing impairments in physical function.