Background: Studies have not examined the relationships between serum vitamin D (SVitD), serum cortisol (SCort), bone mineral density (BMD), and body fat percent (BF%) in elite figure skaters. However, studies of non-athletes have found that BMD is inversely related to SCort and directly related to SVitD, and BF% is inversely related to SVitD and directly related to SCort. It was, therefore, the purpose of this study to assess the relationships between SCort, SVitD, BMD, and BF% in elite figure skaters. Methods: U.S. national team figure skaters were assessed at a national training camp during the summer, 2012. BMD and body composition were measured by dual energy x-ray absorptiometry (DEXA). Blood chemistry values for SVitD and SCort were obtained via venous puncture after an overnight fast, the same morning as the DEXA measurement. Georgia State University Institutional Review Board approval was obtained for the assessment of data collected at this training camp. Results: 24 out of 39 training camp attendees (61.5%) volunteered to be assessed as part of this study. Subjects ranged from 17 to 34 years and included males (n=11) and females (n=12). In all skaters statistically significant negative correlations (2-tailed Spearman) were found between SCort and BMD of the spine (r=-0.458, p=0.032), pelvis (r=-0.532, p=0.011), ribs (r=-0.517, p=0.014), and trunk (r=-0.538, p=0.010). In females, SCort was negatively correlated with BMD of the pelvis (r=-0.664, p=0.026) and trunk (r=-0.609, p=0.047), and was positively correlated with total BF% (r=0.657, p=0.020) and trunk fat % (r=0.708, p=0.010). In males, SCort was significantly correlated with BMD of the ribs (r=-0.627, p=0.039). The 3 skaters (all female) with SCort > 28 mcg/dL had significantly lower mean BMD of the total body, left femoral neck, legs, trunk, and pelvis, and significantly greater BF% of the total body and trunk when compared to the 20 skaters with SCort 7-28 mcg/dL. No significant correlations between SVitD and BMD or BF% were found. A Mann-Whitney U test found no significant differences in BMD and BF% between the 8 skaters with SVitD ≥ 30 ng/mL compared to the 15 skaters with SVitD < 30 ng/mL (p>0.05). Females with SVitD ≥ 30 ng/mL had significantly higher BMD (p=0.041) of the right femoral neck when compared to those with lower SVitD. Conclusions: Correlations consistently found negative associations between SCort cortisol and BMD in multiple assessment areas, particularly those composed of trabecular bone. Higher SCort was also associated with higher BF% in female skaters. Despite spending a great deal of time in indoor facilities, limiting vitamin D creation through sunlight exposure, no significant correlation between SVitD and BMD was found. Female athletes in ‘appearance’ sports, may be predisposed to restrained eating behaviors, which may be associated with elevated SCort. These findings suggest a need for further study of the interaction between SCort, BMD, and BF% in these athletes. The lack of a statistically significant relationship between SVitD and BMD suggests the need to investigate additional factors associated with bone injury risk in athletes.

Background: Studies have consistently found a high prevalence of vitamin D deficiency in adolescents. Few validated dietary intake assessment tools for vitamin D exist for adolescents. Objective: The aim of this study was to determine if a short food frequency questionnaire (SFFQ) can be used to effectively assess vitamin D intake in adolescents compared to a previously validated long food frequency questionnaire (LFFQ). Participants/setting: 140 healthy 6-12 year old (male n=81) Caucasian and African American (n=94) children from Pittsburgh, Pennsylvania completed a SFFQ and LFFQ at two time points 6 months apart. Main outcome measures: Reliability and validity of a SFFQ by comparison with a previously validated LFFQ for children and adolescents. Statistical analysis: Reliability, validity, sensitivity, specificity, positive, and negative predictive values were assessed using Pearson correlation coefficients. Results: Mean vitamin D intake from the SFFQ (range, 434 to 485 IU) was higher than the LFFQ (range, 320 to 378 IU). Overall association between the SFFQ and the LFFQ for vitamin D intake was modest (r=0.36, P<0.001). When stratified by race, the overall degree of association was weak for African Americans (r=0.26, P=0.001) and moderate for Caucasians (r=0.57, P<0.001). Overall reliability testing results were modest and significant for the LFFQ (r=0.28, P=0.002) and SFFQ (r=0.33, P<0.001). Association between mean vitamin D intake from LFFQs and SFFQs was used to determine validity. The association for validity was found to be modest (r=0.51, P<0.001). Sensitivity, specificity, positive predictive value, and negative predictive value for the SFFQ were 90%, 64%, 0.78, and 0.58, respectively. Conclusion: The SFFQ was found to be modestly valid and reliable in an early adolescent population. Associations between African Americans were not as strong as Caucasians which may be due to errors in reporting dietary consumption related to higher body weight.

Objective: The aim of this study is to examine the relationship between vitamin D and calcium intake and obesity in a population of young adolescents who participated in a Vitamin D and Sunlight Exposure study in Pittsburgh, PA. Participants: 252 healthy 6 to 14.9 year old young adolescents (54% male, 69% African American) were recruited between June 2006 and December 2009. Main outcome measures: Weight status, BMI, vitamin D intake, calcium intake, vitamin D and calcium rich food intake. Results: A significant difference by race was observed with 30.1% of African Americans and 8.5% of Caucasians being obese (P<0.01). No difference was found by gender. Median (25%, 75%) vitamin D intake in the total population was 254.9 IU (146.8, 407.3) which is below the level recommended by the Institute of Medicine. Median calcium intake in the total population was 1193.6 mg (752.8, 1161.1) which met recommended guidelines. Median vitamin D intake differed by weight status (normal, overweight, obese) in the total population (259.5 IU, 325.2 IU and 181.9 IU, respectively; P=0.015). A similar pattern was observed for calcium (1193.4 mg, 1416.3 mg and 911.6 mg, respectively; P=0.016). No correlation was found between vitamin D or calcium intake and BMI in the total population or by race and gender. Conclusion: Vitamin D and calcium intake was significantly different based on weight status, particularly in obese and African American subjects. Vitamin D intake in the population was reportedly below recommended guidelines. Further research is necessary to determine the ideal vitamin D and calcium intake in children for optimal health status, including longitudinal studies to better assess the relationship between vitamin D and calcium intake and weight status.

Background: Determinants of vitamin D status are of interest when studying the epidemiology of disease in population groups because vitamin D is now recognized to decrease the risk of diseases such as osteoporosis, cancer, and cardiovascular disease. Understanding modifiable determinants of vitamin D status are important for managing vitamin D deficiency at the individual level and for addressing this issue at population level. Objective: The objective of this study was to evaluate the associations between serum vitamin D status (deficiency and insufficiency) and distinct demographic, dietary, and lifestyle characteristics of adults in the United States using a large, nationally representative sample survey, the National Health and Nutrition Examination Survey (NHANES) 2005-2006. Methods: The study sample consisted of 2340 adults aged 20-59 who had serum 25(OH)D measured and who had completed various questionnaires concerning dietary intake of vitamin D and other lifestyle factors. Multivariate logistic regression was used to estimate the odds ratio (OR) of vitamin D deficiency, insufficiency, and sufficiency in adults based on distinct demographic, dietary, and lifestyle characteristics. Statistical significance was set at α < 0.05. Results: The prevalence of vitamin D deficiency was higher in obese adults than in underweight to normal weight adults (50.9% ± 4.57 vs. 29.3% ± 3.57), higher in adults who reported no sunburns than in adults who reported ≥ 3 sunburns (49.9% ± 3.82 vs. 18.0% ± 3.07), and higher in adults who use sun protective measures regularly than in adults who do not (48.4% ± 3.93 vs. 27.0% ± 3.75). The prevalence of vitamin D deficiency increased as dietary intake of vitamin D decreased. Non-Hispanic black adults were significantly more likely to be vitamin D deficient (OR = 45.27, 95% CI = 17.27-118.64) and insufficient (OR = 9.37, 95% CI = 3.43-25.61) than non-Hispanic white adults. Significant positive associations were found between vitamin D deficiency and several characteristics, namely obesity (OR = 7.43, 95% CI = 4.33-12.77), physical inactivity (OR = 1.63, 95% CI = 1.03-2.58) poor dietary vitamin D intake (OR = 2.34, 95% CI = 1.44-3.81), non-supplement use or supplement use with a low amount of vitamin D (OR = 1.75, 95% CI = 1.05-2.89), and activities that decrease exposure to sunlight (from OR = 2.97, 95% CI = 2.14-4.13 to OR = 5.30, 95% CI = 3.17-8.85). Conclusion: The results of this nationally representative study demonstrate that obesity, physical inactivity, poor dietary intake of vitamin D, and low sunlight exposure increases the risk for vitamin D deficiency in U.S adults. Future studies are needed to investigate whether vitamin D supplementation, sunlight exposure, and vitamin D-fortified foods are efficient in correcting vitamin D deficiency and insufficiency among these groups.

Background: Prevalence of obesity in US children has increased substantially. The influence of vitamin D intake on body mass index (BMI) is yet to be clearly defined. Results are mixed regarding the relationship of vitamin D deficiency with obesity in children. The objective of this study was to examine the association between vitamin D intake and BMI over a 6 month period in pre-to early adolescent children in Pittsburgh, PA. Methods: Secondary analysis was done on 256 healthy 6-14 year old (54% male) Caucasian and African American (70%) children from Pittsburgh, PA. Participants completed a food frequency questionnaire (FFQ) and a Sun Exposure Questionnaire (SEQ) and provided anthropometric measures at 2 time points 6 months apart. Vitamin D intake was compared by BMI status (normal = <85th percentile, overweight = 85th to 95th percentile, obese = >95th percentile) as well as by change in BMI over 6 months. Statistical analysis included descriptive statistics, Kruskal-Wallis analysis of variance, Spearman’s correlation, Chi Square test, and regression analysis (vitamin D intake, gender, race, baseline BMI, total energy intake, sun exposure and sunscreen use). Results: Median reported vitamin D intake was 245.85 IU at baseline and 382.51 IU at 6 month follow up. After subdividing children by BMI, at baseline the obese group reported lowest median intake (188 IU) and at 6 month follow up the normal group reported lowest median intake (374 IU) (P=0.03). Overall relation between vitamin D intake and BMI was significant (P=0.033) but weak (r=-0.015). Regression analysis revealed only baseline BMI status (P=<0.001) as a predictor of 6 month follow up BMI. No relation was observed between change in BMI and vitamin D intake. Conclusion: The results of this study do not support a strong relationship between vitamin D intake and change in BMI status over a 6 month time period.

Thesis (M.A.)--Central Connecticut State University, 2003. / Thesis advisor: Cheryl Watson. " ... in partial fulfillment of the requirements for the degree of Master of Arts in Department of Biological Sciences." Includes bibliographical references (leaves 45-50). Also available via the World Wide Web.

Zugl.: Giessen, Univ., Diss., 2009

OBJECTIVE: To examine the relationships between socioeconomic status (SES), body mass index (BMI), and vitamin D levels in African American (AA) women living in areas with abundant sunshine; and to explore if diabetes moderates these relationships. SIGNIFICANCE: More AA's live in poverty, and experience obesity, diabetes, and chronic disease compared to other groups. Eighty percent of AA women are overweight or obese, and rates of type 2 diabetes is highest in this group. Minority race, obesity, and diabetes increase risks for low vitamin D, and are associated with p DESIGN AND METHOD: A cross-sectional descriptive research design was used to examine the specified relationships. Data from 611 non-pregnant AA women ≥ age 20 from the National Health and Nutrition Examination Survey (NHANES) cycles 2003 - 2006 were studied. SES was measured as poverty to income ratio (PIR), education level, and annual household income. Mean ± SD for BMI was 31 ± 8, and 14ng/ml ± 7ng/ml for vitamin D level. Only 8% of the sample had diabetes (n = 49). One hundred-eighty lived in areas with abundant sunshine. RESULTS: BMI independently predicted the vitamin D level without regard for SES, or geographical locale. Vitamin D supplement use emerged as an independent predictor of vitamin D on covariate analysis. SES did not explain significant variation in the vitamin D level. A moderating influence of diabetes could not be determined. CONCLUSIONS: BMI inversely predicts vitamin D level independent of geographic locale in AA women. Ethno/cultural measures to reduce BMI should be standard in caring for AA women which may affect vitamin D level and/or reduce morbidity and mortality in this group. Persons with low vitamin D suffer with more adverse health outcomes, and future research should examine if vitamin D deficiency accelerates risks for poor health outcomes where BMI is high.

Background Vitamin D deficiency is prevalent in many places across the world. Breastfeeding has been suggested to be a significant predictor of vitamin D deficiency during infancy, which is preventable through proper supplementation. However, whether Hong Kong should adopt the international recommendation for supplementation of exclusive breastfed infants is still not yet answered. Objective: To review the available evidence regarding the association between breastfeeding and vitamin D deficiency during infancy, as well as the effectiveness of vitamin D supplementation of breastfed infants as an intervention measure. Methods A total of 5112 potentially relevant articles were searched and identified from MEDLINE (OVID, Pubmed), Science Citation Index Expanded (ISI Web of Science), Cochrane Central Register of Controlled Trials, EMBASE, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) and Chinese database (CNKI) without restriction from inception to July-06-2012. 5065 articles were excluded after the initial scanning of title and abstracts. 36 were subsequently excluded due to methodological issues. A total of 11 studies were included and reviewed by two independent reviewers. Results This review pooled together a total of 1126 exclusively breast-fed infants for less than one year old from 11 studies. The pooled average prevalence of vitamin D deficiency was 54.2%. The association between breastfeeding and vitamin D deficiency during infancy has been reported consistently, and it was found to be one of the strongest predictors of vitamin D deficiency for infants less than one year old. Sunlight exposure, season, and skin pigmentation were also found to be important affecting factors. Supplementation to breastfed infants with the dosages as recommended by American Academy of Pediatrics (AAP) seem to be effective in lifting up the vitamin D levels. Conclusions The Hong Kong Government and relevant health sectors should conduct local epidemiological study to investigate the problem of concern among our breast-fed infants, and seriously consider or evaluate the AAP recommendation of supplementation. / published_or_final_version / Public Health / Master / Master of Public Health

Background: Vitamin D deficiency is prevalent among Chinese adults in Hong Kong and ignorance and confusion about vitamin D is common throughout the Hong Kong population. Health literacy is a crucial factor that influences the health actions and outcomes of individuals; however, little is known about the relationship between health literacy and behavior of supplementing vitamin D through sunlight exposure. Objective: The aim of the current study was to identify the factors associated with the health literacy of Chinese older adults and to investigate the relationship between health literacy and the behavior of supplementing vitamin D through sunlight exposure. Method: From May 2011 to January 2012, a cross-sectional survey was conducted among cognitively intact Chinese adults aged 60 or above. Recruitment of participants was through 23 residential care homes and 7 elderly community centers. A questionnaire elicited demographic and health literacy information and explored their knowledge about vitamin D, their attitude towards sunlight exposure, and their behavior related to sunlight exposure. Linear regression identified the factors associated with the health literacy among Chinese older adults. Path analysis investigated the relationship between health literacy and the behavior of participants regarding sunlight exposure. Results: Participants and analysis included 648 Chinese adults. Among the population, respondents identified as having inadequate health literacy numbered 52.5%. Five factors, including age, marital status, educational attainment, residential status, and duration of living in residential care homes, had significant association with health literacy. In addition, health literacy had a direct relationship to respondents’ exposure to sunlight (direct effect = .075) and an indirect relationship through their knowledge about vitamin D and their attitude towards sunlight exposure (indirect effect = .015). However, knowledge about vitamin D and attitude towards sunlight exposure did not mediate the association between health literacy and behaviors concerning sunlight exposure. Discussion and Conclusion: The results of this study showed that not only age, marital status, and educational attainment affected health literacy but also residential status and duration of living in residential care homes offered an effect. The study revealed that health literacy had both a direct and indirect relationship to health behavior (e.g., supplementing vitamin D through sunlight exposure). Health care professionals should note the relationship between health literacy and health behavior. Health education intervention about vitamin D supplement should focus training on individuals’ health literacy rather than their knowledge about vitamin D or attitude towards sunlight exposure. / published_or_final_version / Nursing Studies / Master / Master of Philosophy