Mediterranean Diet, Physical Activity, and Bone Health in Older Adults: A Secondary Analysis of a Randomized Clinical Trial.

IMPORTANCE

Understanding the effects of diet and physical activity on bone health may help to mitigate concomitant weight loss- and age-related bone deterioration.

OBJECTIVE

To evaluate the effects of a weight-loss lifestyle intervention on bone mineral density (BMD), bone mineral content (BMC), and low BMD prevalence.

DESIGN, SETTING, AND PARTICIPANTS: The 3-year, parallel-group Prevención con Dieta Mediterránea-Plus (PREDIMED-Plus) randomized clinical trial was conducted at recruiting centers in Spain from October 2013 to December 2016. Men and women (aged 55-75 years) with metabolic syndrome and overweight or obesity, as well as access to dual-energy x-ray absorptiometry (DXA) (from 4 centers in Navarra, Mallorca, Reus, and León), were included in this prespecified secondary analysis. The analysis was conducted from September 1 to October 30, 2024.

INTERVENTION

Participants were randomly allocated (1:1) to the intervention or the control. The intervention group followed an energy-reduced Mediterranean diet and increased physical activity, whereas the control group was advised to follow an ad libitum Mediterranean diet with no physical activity promotion.

MAIN OUTCOMES AND MEASURES

BMD (total femur, lumbar spine [L1-L4], and femoral trochanter) and total BMC were measured using DXA at baseline and at 1 and 3 years of follow-up. T scores from BMD variables were determined, and osteopenia or osteoporosis status was defined as low BMD. Linear and logistic 2-level mixed models were used for main analyses including participants lost to follow-up. Intention-to-treat analysis, completers case analysis, and sensitivity analysis were additionally performed.

RESULTS

This study included 924 older adults (mean [SD] age, 65.1 [5.0] years; 454 women [49.1%] and 470 men [50.9%]). Significant differences in mean changes between groups were observed, with an overall 3-year intervention increase in the intervention group (n = 460) compared with the control group (n = 464) in lumbar spine (L1-L4) BMD (between-group differences, -0.1 [95% CI, -0.8 to 0.8] g/cm2 after 1 year and 0.9 [95% CI, 0.1-1.8] g/cm2 after 3 years; overall P = .05). This protective association was observed for women (between-group differences, -0.1 [95% CI, -1.3 to 1.1] g/cm2 after 1 year and 1.8 [95% CI, 0.6-2.9] g/cm2 after 3 years; overall P = .005) but not for men. No overall 3-year intervention effect on total BMC and low BMD prevalence was observed.

CONCLUSIONS AND RELEVANCE

In the PREDIMED-Plus trial, an energy-reduced Mediterranean diet and physical activity lifestyle intervention mitigated weight loss- and age-related BMD decline among older women with metabolic syndrome compared with conventional ad libitum Mediterranean diet recommendations. Weight-loss lifestyle interventions with longer follow-up are warranted in the future to confirm these results in relation to bone health.

TRIAL REGISTRATION

ISRCTN Registry Identifier: ISRCTN89898870.