A 3-year randomized clinical trial has found that a weight-loss lifestyle intervention combining an energy-reduced Mediterranean diet with physical activity may produce beneficial effects on bone mineral density, particularly at the lumbar level, in older women with metabolic syndrome.
The findings, published in JAMA Network Open, suggest that such interventions may help preserve bone health during intentional weight loss in populations at risk for osteoporotic fractures.
Researchers recruited 924 older adults (mean age = 65.1 years) with metabolic syndrome and overweight or obesity who were randomly allocated to either an intervention group following an energy-reduced Mediterranean diet with increased physical activity or a control group following an ad libitum Mediterranean diet without specific physical activity recommendations.
"In the PREDIMED-Plus trial, an energy-reduced Mediterranean diet and physical activity lifestyle intervention mitigated weight loss– and age-related bone mineral density [BMD] decline among older women with metabolic syndrome compared with conventional ad libitum Mediterranean diet recommendations," the study authors reported.
The intervention group showed a protective effect on lumbar spine BMD after 3 years of follow-up. Significant differences in mean changes between the groups were observed with an overall 3-year intervention increase in the intervention group compared with the control group in lumbar spine (L1-L4) BMD (between-group differences = −0.1, 95% confidence interval [CI] = –0.8 to 0.8 g/cm² after 1 year; 0.9, 95% CI = 0.1–1.8 g/cm² after 3 years).
This protective association was observed specifically for women (between-group differences = −0.1, 95% CI = –1.3 to 1.1 g/cm² after 1 year; 1.8, 95% CI = 0.6–2.9 g/cm² after 3 years; overall P = .005) but not for men. In the intention-to-treat analysis, the intervention also showed beneficial effects on total femur BMD and femoral trochanter BMD in women over 3 years.
The researchers utilized dual-energy x-ray absorptiometry to measure BMD at the total femur, lumbar spine (L1-L4), and femoral trochanter, as well as total bone mineral content at baseline and at 1 and 3 years of follow-up.
No overall intervention effect on total bone mineral content and low BMD prevalence was observed over the 3-year period. The researchers noted that the findings were robust across multiple analytical approaches, including completers case analysis and sensitivity analyses.
The intervention also produced significant weight loss. Total body weight decreased 3.3% (3.5% in men and 3% in women) and 3% (3.4% in men and 2.5% in women) over 1 and 3 years, respectively, in the intervention group compared with 0.4% (0.3% in men and 0.6% in women) and 0.7% (0.5% in men and 0.9% in women) in the control group.
The researchers suggested that the observed sex differences may be related to the fact that "women have increased BMD values at the lumbar spine compared with men and also are more prone to bone changes accompanying excess weight than men. Moreover, menopause itself is a risk factor for osteoporosis, and estrogen loss in women at menopause may lower lumbar spine BMD."
"Weight-loss lifestyle interventions based on an energy-reduced Mediterranean diet and physical activity promotion delivered to older women at risk of bone disturbances may be a feasible strategy for potentially mitigating the effects of concomitant weight loss on age-related decline in bone mineral density," concluded investigators.
The PREDIMED-Plus intervention included specific physical activity recommendations, encouraging participants to gradually increase their physical activity to meet the World Health Organization recommendation of 150 minutes of moderate to vigorous physical activity per week. Participants were encouraged to walk for a minimum of 45 minutes per day, 6 days per week, and to engage in strength, flexibility, and balance exercises 3 days per week, along with 30- to 40-minute sessions of resistance training 2 days per week.
Disclosures can be found in the published article.
