Bone Mineral Density in Breath-Hold Divers: Investigating the Role of Physical Activity, Dietary Habits and Supplementation Practices

Objectives: This study investigated the relationship between physical activity (PA) type, dietary habits (DH), and supplementation practices (SP) with bone mineral density (BMD) among breath-hold divers.Methods: This cross-sectional study included 28 breath-hold divers (24 males, 4 females) aged 23-53 years, residing in Athens, Greece.Participants had a mean age of 41.09 years, trained breath-hold diving for 8.93 years and engaged in 7.67 hours of weekly training on average.PA, DH and SP were assessed using comprehensive and structured questionnaire.BMD was measured using dual-energy X-ray absorptiometry (DEXA).Multiple linear regression (MLR) analysis was used to examine the effects of age, smoking status, type of PA apart from diving, frequency of consumption of dairy products, vitamin D, calcium and magnesium supplementation on BMD.Results: Eight participants practiced only non-weightbearing sports, six were smokers, six excluded milk from their diet, and three had lactose intolerance.The mean value of participants BMD was 1.28 g/cm 2 .MLR for BMD was not statistically significant (p 0.814), with an R 2 of 0.184 and adjusted R 2 of -0.159.Age (B 0.002, p 0.637), smoking (B 0.120, p 0.089), practicing only non-weight bearing sports (B -0.07, p 0.918), milk/yogurt consumption frequency (B 0.008, p 0.763), cheese consumption frequency (B -0.011, p 0.701), supplementation with vitamin D (B -0.006, p 0.935), calcium (B 0.016, p 0.882), and magnesium (B 0.006, p 0.918) were not significant predictors of BMD.Conclusions: Breath-hold diving is a non-weight-bearing sport that provides low stimulation for adaptation of skeletal system.Adequate intakes of calcium, vitamin D, magnesium, and protein are important for bone metabolism homeostasis.However, the lack of significant relationships between BMD with DH and SP may reflect the small sample size.Larger studies are needed to explore the correlation between NWB activities and nutrition in bone health.