Sex Differences of Vitamin D Status across BMI Classes: An Observational Prospective Cohort Study

Abstract

Growing evidence reported that vitamin D deficiency is a common finding in obesity. Vitamin D status also seems to be sex-related, although little is known regarding this association. Therefore, the aim of this study was to investigate the sex-related differences of serum 25OH vitamin D (25OHD) concentrations across body mass index (BMI) classes and, if there were any differences, whether they could be explained by sex-related differences in body composition. We enrolled 500 subjects (250 males, age 37.4 ± 11.8 years; 250 females, age 36.6 ± 11.8 years). Body composition was assessed by bioelectrical impedance analysis (BIA) phase-sensitive system. Serum 25OHD concentration was quantified by a direct, competitive chemiluminescence immunoassay. Vitamin D deficiency was defined as a serum 25OHD concentrations < 20 ng/mL (50 nmol/L). Stratifying the sample population according to sex and BMI categories, 25OHD concentrations were significantly higher in males compared to females in all BMI classes and decreased along with the increase of BMI values. Females with vitamin D deficiency had higher fat mass (FM) % compared to males with vitamin D deficiency. The 25OHD concentrations inversely correlated with FM % in both sexes. In a multiple regression analysis model, sex, FM %, and BMI were predictive factors of 25OHD concentration. In conclusion, our study suggests that 25OHD concentrations were lower in females than males across all BMI categories. Given the tight correlation between 25OHD concentrations and FM %, it can be hypothesized that the lower 25OHD concentrations in females than males can be explained by the fact that females have a higher amount of fat than males.Nutrients 2019, 11, 3034 2 of 12 coming from The National Health and Nutrition Examination Survey (NHANES) 2005 to 2006 provide information regarding the prevalence of vitamin D deficiency in people with obesity and at normal weight. The 2005 to 2006 NHANES included certain subgroups of the US population, including low-income persons, older adults aged 60 years or older, African Americans, and Mexican Americans, to provide a more in-depth snapshot of these population groups. A total of 12,862 individuals were sampled in the 2005 to 2006 NHANES. Among the sampled individuals, 10,348 (80.5%) participated in the interview and 8306 (65%) provided valid data on vitamin D measurement. The findings of this study reported that the prevalence of vitamin D deficiency (vitamin D concentration < 20 ng/mL) has been reported to be higher (53.8%) in subjects with obesity compared to normal weight (33%) [6]. Body fat may represent a reservoir for vitamin D storage, reducing its bioavailability [7]. An inverse correlation between serum 25OHD concentration and magnitude of weight loss in people with obesity after bariatric surgery confirms this theory [8]. Indeed, large accrual in adipose tissue depot implies that vitamin D3 could not be appropriately released into the general circulation to support serum 25OHD concentrations. However, the sequestration and the inappr...

The Sun’s Vitamin in Adult Patients Affected by Prader–Willi Syndrome

“…The serum levels of 25OHD were quantified by a direct competitive chemiluminescence immunoassay (CLIA) (Liaison, DiaSorin, Saluggia, Italy), with a specificity of 100% for 25OHD. The analytical measurement range of detection was 4-150 ng/mL, whereas the intra-assay CVs were 5%, 3%, and 5%, and the inter-assay CVs were 10%, 5%, and 8% for low, medium, and high points of the standard curve, respectively (as previously reported in [53][54][55][56]). The vitamin D deficiency was defined as 25OHD levels < 20 ng/mL (50 nmol/L), vitamin D insufficiency as 25OHD levels between 21 and 29 ng/mL (from 53 to 73 nmol/L) and vitamin D sufficiency as 25OHD levels ≥30 ng/mL (75 nmol/L) [57].…”

Does Sars-Cov-2 threaten our dreams? Effect of Quarantine on Sleep Quality and Body Mass Index

“…Finally the house con nement imposed by quarantine could be associated to the decreased intake of fresh food, as fruit, vegetables and sh, all food rich in vitamins (including vitamin C, beta-carotene, and vitamin D), minerals (including selenium and zinc) and omega 3 fatty acids with anti-in ammatory and antioxidants activities. The low consumption of these micronutrients is associated with both obesity and sleep disturbance [54][55][56]; in particular, vitamin D plays a key role in the relationship between obesity and sleep disturbances [57][58][59][60].…”

Serum vitamin D level may be associated with body weight and body composition in male adolescents; a longitudinal study

“…On the other hand, sex may influence on the level of vitamin D. Muscogiuri et al found that 25OHD concentration was higher in males compared with females in all BMI groups. Males with vitamin D deficiency had lower fat mass compared with females [42].…”