Dietary fiber intake is not associated with incident hip fractures in men, according to study results published in Nutrition and Health.

Prior study data have suggested that dietary fiber may be protective against bone mineral density (BMD) loss at the femoral neck in men. However, it remains unclear whether dietary fiber intake also reduces the risk for incident hip fractures.

To further understand the relationship between fracture risk and dietary fiber intake, the researchers of the current analysis collected data from men enrolled in 3 existing cohort studies, including the Framingham Osteoporosis Study (FOS) Original cohort; the FOS Offspring cohort; and the Concord Health and Ageing in Men Project (CHAMP). Each of these studies is a longitudinal, community-based cohort of older adults who were followed up with for age-related clinical outcomes, including osteoporotic fractures. Each study captured dietary fiber intake by a Food Frequency Questionnaire or diet history. Incident hip fractures were defined as a medically confirmed first occurrence of osteoporotic fracture at the proximal femur.

Cox proportional hazard models were used to estimate the hazard ratios (HRs) for incident fracture based on dietary fiber levels. A random-effects model was used to estimate the pooled risk for fracture in the combined cohort. Models were adjusted for age, body mass index, height, physical activity level, and diet parameters including total energy intake, total calcium intake, and dietary quality. 

The study enrolled 367 men from the FOS Original cohort, 1730 men from the FOS Offspring cohort, and 782 men from the CHAMP cohort. Mean age of participants was 75.3±5.1 years in the FOS Original cohort; 58.8±9.8 years in the FOS Offspring cohort; and 81.4±4.5 years in the CHAMP cohort. Median dietary fiber intake in the FOS Original, FOS Offspring, and CHAMP cohorts was 18.2 g/day (interquartile range [IQR], 13.4-24.7 g/day), 17.6 g/day (IQR, 13.5-24.6 g/day), and 26.3 g/day (IQR, 21.1-32.7 g/day), respectively. Mean follow-up duration was highest in the FOS Offspring cohort (11.0±5.9 years), followed by the FOS Original cohort (8.5±6.2 years) and the CHAMP cohort (5.2±1.5 years).

A total of 72 incident hip fractures were observed (24 in the FOS Original cohort, 19 in the FOS Offspring cohort, and 29 in the CHAMP cohort). Dietary fiber was not significantly associated with risk for incident hip fracture according to any analyses. Pooled risk for hip fractures was slightly lower in tertile 3 vs tertile 1 of dietary fiber consumption, but the difference was not statistically significant (HR, 0.80; 95% CI, 0.39-1.66; P =.56).

Study limitations included the use of self-report to capture dietary fiber intake, which may have led to underestimates. Further, models were not adjusted for the use of osteoporosis treatments, which may have confounded the observed association between diet and fracture risk.  

“The earlier observed association showing a modest inverse relationship of dietary fiber with femoral neck BMD loss may not be sufficient to confer further protection against hip fractures,” the researchers wrote. “Future studies are warranted to verify the relationship between fiber intake and bone fractures.”

Disclosure: Two study author(s) declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures. 

Reference

Dai Z, Hirani V, Sahni S, et al. Association of dietary fiber and risk of hip fracture in men from the Framingham Osteoporosis Study and the Concord Health and Ageing in Men Project. Nutr Health. Published online May 4, 2021. doi:10.1177/02601060211011798