Dietary Inflammatory Index and Fractures in Midlife Women: Study of Women's Health Across the Nation

Context While evidence suggests that chronic, low-grade inflammation is a risk factor for bone loss and fractures, the potential relation between an inflammatory dietary profile and greater fracture risk is uncertain. Objective We examined whether a more inflammatory diet, consumed during pre- and early perimenopause, is associated with more incident fractures starting in the menopause transition (MT) and continuing into postmenopause. Methods Dietary inflammatory potential was quantified using 2 energy-adjusted dietary inflammatory index scores: one for diet only (E-DII), and one for diet plus supplements (E-DII-S). We included 1559 women from the Study of Women's Health Across the Nation, with E-DII and E-DII-S scores from the baseline visit (during pre- or early perimenopausal), and up to 20 years of follow-up. We excluded women using bone-beneficial medications at baseline; subsequent initiators were censored at first use. The associations of E-DII or E-DII-S (each tested as separate exposures) with incident fracture were examined using Cox proportional hazards regression. Results Adjusted for age, BMI, cigarette use, diabetes, MT stage, race/ethnicity, prior fracture, bone-detrimental medication use, aspirin or nonsteroidal anti-inflammatory drug use, and study site, greater E-DII and E-DII-S (tested separately) were associated with more future fractures. Each SD increment in E-DII and E-DII-S predicted 28% (P = .005) and 21% (P = .02) greater fracture hazard, respectively. Associations were essentially unchanged after controlling for bone mineral density. Conclusion A more pro-inflammatory diet in pre- and early perimenopause is a risk factor for incident fracture. Future studies should consider whether reducing dietary inflammation in midlife diminishes fracture risk.