Prevalence of Lifestyle Practices That Might Affect Bone Health in Relation to Vitamin D Status Among Female Saudi Adolescents

Background: Prevention of osteoporosis begins in childhood and adolescence, as most bone mass is accumulated during the first 2 decades of life, with 90% to 95% of an adult's bone mineral content being achieved by the end of adolescence. Therefore, targeting modifiable behaviors among adolescents has an important effect on attaining adequate peak bone mass and minimizing risks for future fractures.

Objectives: The aims of this study were to estimate the prevalence of behaviors affecting bone health and vitamin D status and to identify factors associated with vitamin D deficiency among female Saudi adolescents.

Methods: Several modifiable risk factors that influence bone health include low consumption of dairy products, physical inactivity, insufficient sun exposure, smoking, excessive consumption of soft drinks and caffeine, and vitamin D deficiency. A cross-sectional analytical study was conducted in secondary schools in Jeddah City with 421 randomly selected female adolescents. A predesigned questionnaire was used for data collection, and blood samples were collected to measure levels of vitamin D. A χ test and correlation coefficient were used to identify the association between vitamin D and the independent variables. Mean (SD) age was 17.2 y (+1.2 y). Mean vitamin D level was 46 nmol/L (+24.6 nmol/L), ranging from 10.8 to 150.8 nmol/L.

Results: The adolescents reported low consumption of dairy products, low prevalence of sun exposure, and low physical inactivity. Prevalence of vitamin D deficiency was 67.5%, and insufficiency was 21%. There were no significant associations between vitamin D status and sociodemographic characteristics; coffee and tea intake; anthropometric measurements; and calcium and/or vitamin D supplementation. Intake of dairy products was significantly positively correlated with vitamin D levels.

Conclusions: This study indicated that female Saudi adolescents are at significant risk for developing osteoporosis on the basis of the prevalence of risky behaviors, including low consumption of dairy products, high consumption of soft drinks, deficiency in physical exercise, low sun exposure, and high prevalence of vitamin D deficiency and insufficiency.