Seasonal variability of the vitamin D effect on physical fitness in adolescents.

Studies investigating the relationship between vitamin D and physical fitness in youth have provided inconsistent findings. Recent evidence indicates that the expression of receptors and vitamin D-modulated genes in young subjects has a seasonal profile. Therefore, we investigated the role of vitamin D on physical fitness across seasons in a total of 977 male adolescents. Anthropometrics, lifestyle, dietary habits, biochemical profiles and physical fitness were studied. Multiple linear regression models, including pairwise interaction terms involving total 25-OH-vitamin D, were fitted. The interacting effect of season and total 25-OH-vitamin D had a significant influence on physical fitness performance (spring and total 25-OH-vitamin D: ß 0.19, SE 0.07, p = 0.007; summer and total 25-OH-vitamin D: ß 0.10, SE 0.06, p = 0.11; autumn and total 25-OH-vitamin D: ß 0.18, SE 0.07, p = 0.01), whereas the main effect of total 25-OH-vitamin D alone was not significant (p = 0.30). Body fat percentage, recreational physical activity level, time spent per day gaming/TV-watching, smoking, and hemoglobin levels were also related to the physical fitness performance score. Future studies should further explore the role of seasonal-dependent effects of vitamin D on health.

Vitamin D Status Among Male Late Adolescents Living in Southern Switzerland: Role of Body Composition and Lifestyle.

BACKGROUND: Poor vitamin D status is a worldwide health problem. Yet, knowledge about vitamin D status among adolescents in Southern Europe is limited. This study investigated concentrations and modulating factors of vitamin D in a healthy population of male late adolescents living in Southern Switzerland. METHODS: All apparently healthy subjects attending for the medical evaluation before the compulsory military service in Southern Switzerland during 2014-2016 were eligible. Dark-skin subjects, subjects on vitamin D supplementation or managed with diseases or drugs involved in vitamin D metabolism were excluded. Anthropometric measurements (body height, weight, fat percentage, mid-upper arm and waist circumference) and blood sampling for total 25-hydroxy-vitamin D, total cholesterol and ferritin concentrations testing, were collected. Participants filled in a structured questionnaire addressing their lifestyle. Characteristics of the subjects with adequate (≥50 nmol/L-≤250 nmol/L) and insufficient (<50 nmol/L) vitamin D values were compared by Kruskal-Wallis test or χ2 test. Odds ratios for 25-hydroxy-vitamin D insufficiency were calculated by univariate and AIC-selected multiple logistic regression models. RESULTS: A total of 1045 subjects volunteered to participate in the study. Insufficient concentrations of vitamin D were detected in 184 (17%). The season of measurement was the most significant factor associated with vitamin D levels and approximately 40% of subjects presented insufficient vitamin D concentrations in winter. After model selection, body fat percentage, frequency and site of recreational physical activity, and the seasonality were significantly associated with the risk of vitamin D insufficiency. CONCLUSIONS: Among healthy male late adolescents in Southern Switzerland, about one every fourth subject presents a poor vitamin D status in non-summer seasons. Body fat percentage, frequent and outdoor recreational physical activity are modulating factors of vitamin D status in this population.

Carotenoid Intake from Natural Sources and Head and Neck Cancer: A Systematic Review and Meta-analysis of Epidemiological Studies.

Because of their role as antioxidants, the intake of carotenoids has been hypothesized to reduce the risk of head and neck cancer (HNC). We conducted a systematic review and meta-analysis of the epidemiological studies to investigate whether the intake of specific carotenoids from dietary sources, as well as combined carotenoids, is associated with the risk of HNC according to cancer subsites. A comprehensive literature search of the Medline and Scopus databases was conducted. Sixteen articles were identified from the literature search, of which 15 were case-control studies and one prospective cohort study. The risk reduction associated with ß-carotene equivalents intake was 46% (95% CI, 20%-63%) for cancer of oral cavity and 57% (95% CI, 23%-76%) for laryngeal cancer. Lycopene and ß-cryptoxanthin also reduced the risk for laryngeal cancer; the ORs for the highest category compared with the lowest one of carotenoid intake were 50% (95% CI, 11%-72%) and 59% (95% CI, 49%-67%), respectively. Lycopene, α-carotene, and ß-cryptoxanthin were associated with at least 26% reduction in the rate of oral and pharyngeal cancer (95% CI, 2%-44%). Our systematic review and meta-analysis on dietary carotenoids intake and HNC showed carotenoids to act protectively against HNC, in relation to most of single nutrients and subsites.

Folate intake and the risk of oral cavity and pharyngeal cancer: a pooled analysis within the International Head and Neck Cancer Epidemiology Consortium.

There are suggestions of an inverse association between folate intake and serum folate levels and the risk of oral cavity and pharyngeal cancers (OPCs), but most studies are limited in sample size, with only few reporting information on the source of dietary folate. Our study aims to investigate the association between folate intake and the risk of OPC within the International Head and Neck Cancer Epidemiology (INHANCE) Consortium. We analyzed pooled individual-level data from ten case-control studies participating in the INHANCE consortium, including 5,127 cases and 13,249 controls. Odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) were estimated for the associations between total folate intake (natural, fortification and supplementation) and natural folate only, and OPC risk. We found an inverse association between total folate intake and overall OPC risk (the adjusted OR for the highest vs. the lowest quintile was 0.65, 95% CI: 0.43-0.99), with a stronger association for oral cavity (OR = 0.57, 95% CI: 0.43-0.75). A similar inverse association, though somewhat weaker, was observed for folate intake from natural sources only in oral cavity cancer (OR = 0.64, 95% CI: 0.45-0.91). The highest OPC risk was observed in heavy alcohol drinkers with low folate intake as compared to never/light drinkers with high folate (OR = 4.05, 95% CI: 3.43-4.79); the attributable proportion (AP) owing to interaction was 11.1% (95% CI: 1.4-20.8%). Lastly, we reported an OR of 2.73 (95% CI:2.34-3.19) for those ever tobacco users with low folate intake, compared with nevere tobacco users and high folate intake (AP of interaction =10.6%, 95% CI: 0.41-20.8%). Our project of a large pool of case-control studies supports a protective effect of total folate intake on OPC risk.

Nutrient-based dietary patterns and the risk of oral and pharyngeal cancer.

The relationship between diet and oral and pharyngeal cancer has been rarely addressed considering dietary patterns. We examined this issue using data from a case-control study carried out between 1992 and 2005. Cases were 804 incident oral cancers hospitalized in 3 Italian areas. Controls were 2080 subjects hospitalized for non-neoplastic diseases. Dietary habits were investigated through a validated 78-item food-frequency questionnaire. Overall and individual measures of sampling adequacy were calculated to assess if applying a factor analysis or not. A posteriori dietary patterns were identified through a principal component factor analysis performed on a selected set of 29 nutrients. The internal reproducibility, robustness and reliability of the identified patterns were evaluated. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using unconditional multiple logistic regression models on quintiles of factor scores. The measures of sampling adequacy were generally satisfactory. We identified five major dietary patterns named Animal products, Starch-rich, Vitamins and fiber, Unsaturated fats and Retinol and niacin. The Animal products pattern was positively associated with oral cancer (OR=1.56, 95% CI: 1.13-2.15 for the highest vs. the lowest score quintile), whereas the Starch-rich pattern (OR=0.71, 95% CI: 0.50-0.99), the Vitamins and fiber pattern (OR=0.47, 95% CI: 0.34-0.65) and the Unsaturated fats pattern (OR=0.63, 95% CI: 0.45-0.86) were inversely associated with it. These findings confirm that diets rich in animal origin and animal fats are positively, and those rich in fruit and vegetables, and vegetable fats inversely related to oral and pharyngeal cancer risk.

Nutrient-based dietary patterns and laryngeal cancer: evidence from an exploratory factor analysis.

BACKGROUND: The issue of diet and laryngeal cancer has been rarely addressed considering the potential role of dietary patterns. METHODS: We examined this association using data from a case-control study carried out between 1992 and 2000. Cases were 460 histologically confirmed incident laryngeal cancers hospitalized in two Italian areas. Controls were 1,088 subjects hospitalized for acute nonneoplastic diseases unrelated to tobacco or alcohol consumption. Dietary habits were investigated through a 78-item food frequency questionnaire. A posteriori dietary patterns were identified through principal component factor analysis carried out on a selected set of 28 major nutrients. The internal reproducibility, robustness, and reliability of the identified patterns were evaluated. Odds ratios (OR) of laryngeal cancer and 95% confidence intervals (95% CI) were estimated using unconditional multiple logistic regression models on quartiles of factor scores. RESULTS: We identified five major dietary patterns named "animal products," "starch-rich," "vitamins and fiber," "vegetable unsaturated fatty acids," and "animal unsaturated fatty acids." The vitamins and fiber dietary pattern was inversely associated with laryngeal cancer (OR, 0.35; 95% CI, 0.24-0.52 for the highest versus the lowest score quartile), whereas the animal products (OR, 2.34; 95% CI, 1.59-3.45) and the animal unsaturated fatty acids (OR, 2.07; 95% CI, 1.42-3.01) patterns were directly associated with it. There was no significant association between the vegetable unsaturated fatty acids and the starch-rich patterns and laryngeal cancer risk. CONCLUSION: These findings suggest that diets rich in animal products and animal fats are directly related, and those rich in fruit and vegetables inversely related, to laryngeal cancer risk.

Nutrient dietary patterns and gastric cancer risk in Italy.

BACKGROUND: There have been several studies on diet and gastric cancer, but only a few investigations have considered the role of dietary patterns. METHODS: We investigated gastric cancer risk in relation to dietary patterns in a case-control study conducted in northern Italy between 1997 and 2007, including 230 patients with incident, histologically confirmed gastric cancer and 547 frequency-matched controls, admitted to the same hospitals as cases, with acute nonneoplastic conditions. Dietary habits were investigated through a validated food frequency questionnaire including 78 foods and beverages. We identified a posteriori dietary patterns on a selected set of 28 micro- and macro-nutrients through an exploratory principal component factor analysis. We estimated the odds ratios (OR) and the corresponding 95% confidence intervals (95% CI) using conditional logistic regression models on quartiles of factor scores. RESULTS: We identified four major dietary patterns, named "animal products", "vitamins and fiber", "vegetable unsaturated fatty acids", and "starch-rich". We observed a positive association between gastric cancer risk and the "animal products" (OR, 2.13; 95% CI, 1.34-3.40, for the highest versus the lowest score quartile) and the "starch-rich" (OR, 1.67; 95% CI, 1.01-2.77) dietary patterns. The "vitamins and fiber" pattern (OR, 0.60; 95% CI, 0.37-0.99) was inversely associated with gastric cancer, whereas no significant association emerged with the "vegetable unsaturated fatty acids" pattern (OR, 0.89; 95% CI, 0.56-1.42). CONCLUSIONS: Our analysis suggests a protective effect against gastric cancer risk of dietary patterns rich in fruits and vegetables, and a positive association of dietary patterns rich in meats and animal fats and starchy foods.