S-25OHD Is Associated With Hand Grip Strength and Myopathy at 5 Years in Girls: An Odense Child Cohort Study

Birth season associates with multiple anthropometric traits in Estonian children

Seasonal variation in maternal exposure to sunlight during pregnancy, which relates to variation in vitamin D and other micronutrient availability for a fetus, is a prevalent explanation for the variation of offspring traits with birth season. However, little consensus exists about the pregnancy period during which the fetus is most sensitive to maternal UV exposure and which offspring traits are most sensitive. We examined the association between 11 anthropometric traits and birth season/month among 18,459-23,876 Estonian children born in 1937-62. Nine traits showed seasonal patterns, which were generally weak, compared to the effects of family socioeconomic position (SEP). Most prominent nonlinear associations between offspring traits and birth month emerged among children of mothers in unskilled manual professions. A possible explanation is that the growth of children in high-SEP families is more strongly buffered against any external exposures (including possible shortage of maternally synthesised vitamin D and essential micronutrient availability) than in low-SEP settings. For most traits, children born in spring/summer were larger than those born in autumn/winter. Hip width, trunk length and weight showed the most distinct seasonal patterns. If these birth-season-related patterns are related to maternal sunlight exposure, our results support the view that UV exposure benefits offspring growth towards the end of pregnancy. It is also possible that children born in spring and summer benefitted from the seasonally increasing nutrient availability during the first post-natal months.

Vitamin D status and muscle strength in a pan-European cohort of children and adolescents with normal weight and overweight/obesity

This aimed to investigate associations between the vitamin D status and handgrip strength in children and adolescents considering weight status. Participants aged 7 to < 16 years from the European IDEFICS/I.Family cohort were included. Serum 25-hydroxyvitamin D [25(OH)D] and handgrip strength were measured in 2013/2014. In multivariable logistic regression models, we investigated the association of vitamin D status with handgrip strength adjusted for demographic variables, BMI z-score, sports club membership, screen time and UV intensity. Vitamin D-sufficient children had higher odds for a high handgrip strength (OR = 1.92, 95%-CI: 1.12, 3.30), but this association was limited to children with thinness/normal weight (OR = 2.60, 95%-CI: 1.41-4.81). Children with overweight (OR = 2.64, 95%-CI: 2.00, 3.49) and obesity (OR = 4.53, 95%-CI: 2.93, 7.02) were more likely to have a high handgrip strength than thin/normal weight children.

CONCLUSIONS

The positive association of vitamin D with muscle strength in our study is limited to children with low and normal BMI. In children with overweight or obesity, the higher muscle strength seems to superimpose the association with vitamin D. Overall, our results indicate the importance of sufficient levels of vitamin D and offers physical activity perspectives for children with overweight and obesity.

STUDY REGISTRATION

ISRCTN: https://doi.org/10.1186/ISRCTN62310987 .

WHAT IS KNOWN

• Studies have shown a positive association between vitamin D status and handgrip strength in older adults while studies in children and adolescents are scarce. • Conflicting results were found on whether overweight and obesity are associated with reduced or increased handgrip strength compared to normal weight.

WHAT IS NEW

• The results of this large pan-European study in children and adolescents indicate that a sufficient vitamin D status is associated with better handgrip strength, particularly in participants with thinness/normal weight. • Children with overweight and obesity have a higher handgrip strength as compared to children with thinness/normal weight which seems to superimpose the positive association between vitamin D status and handgrip strength in this group.

Nutrition for Children and Adolescents Who Practice Sport: A Narrative Review

At a developmental age, adequate physical activity is fundamental to overall health and well-being and preventing obesity. Moreover, establishing active behavior can help children and adolescents meet their growth and neurodevelopmental goals. Nutritional requirements vary according to intensity, frequency, and practiced physical activity or sport; therefore, pediatricians should give children and adolescents and their families adequate counseling, avoiding both nutrient deficiencies and excessive or inadequate supplement intake. The focus should be not only on sports performance but also on the child's well-being, growth, and neurodevelopment. Our narrative review aims to discuss the nutritional needs of children and adolescents who practice physical activity, non-competitive sports activity, and elite sports activity while also analyzing the role of food supplements and the risk of eating disorders within this category of subjects.

Vitamin D supplementation and increased dairy protein intake do not affect muscle strength or physical function in healthy 6-8-year-old children: the D-pro randomized trial

PURPOSE

To investigate separate and combined effects of vitamin D supplementation during the extended winter and increased dairy protein intake on muscle strength and physical function in children, and furthermore to explore potential sex differences.

METHODS

In a 2 × 2-factorial, randomized winter trial, 183 healthy, 6-8-year-old children received blinded tablets with 20 µg/day vitamin D3 or placebo, and substituted 260 g/day dairy with yogurts with high (HP, 10 g protein/100 g) or normal protein content (NP, 3.5 g protein/100 g) for 24 weeks during winter at 55° N. We measured maximal isometric handgrip and leg press strength, and physical function by jump tests and a 30 s sit-to-stand test. Physical activity was measured by 7-day accelerometry.

RESULTS

Baseline (mean ± SD) serum 25-hydroxyvitamin D was 80.8 ± 17.2 nmol/L, which increased to 88.7 ± 17.6 nmol/L with vitamin D supplementation and decreased to 48.4 ± 19.2 nmol/L with placebo. Baseline protein intake was 15.5 ± 2.4 E%, which increased to 18.4 ± 3.4 E% with HP and was unchanged with NP. We found no separate or combined effects of vitamin D supplementation and/or increased dairy protein intake on muscle strength or physical function (all P > 0.20). There was an interaction on the sit-to-stand test (Pvitamin×yogurt = 0.02), which however disappeared after adjusting for physical activity (P = 0.16). Further, vitamin D supplementation increased leg press strength relatively more in girls compared to boys (mean [95% CI] 158 [17, 299] N; Pvitamin×sex = 0.047).

CONCLUSION

Overall, vitamin D and dairy protein supplementation during the extended winter did not affect muscle strength or physical function in healthy children. Potential sex differences of vitamin D supplementation should be investigated further. REGISTERED AT CLINICALTRIALS.GOV: NCT0395673.

Maternal Testosterone Concentrations in Third Trimester and Offspring Handgrip Strength at 5 Years: Odense Child Cohort

BACKGROUND

Maternal testosterone in pregnancy may have conditioning effects on offspring muscle strength.

PURPOSE

To investigate possible associations between maternal testosterone concentrations in third trimester and offspring handgrip strength (HGS) at 5 years.

METHODS

In the prospective, population-based Odense Child Cohort, total testosterone (TT) at gestational week 27-28 and 5-year HGS were measured in 1017 mother-child pairs. TT was measured by liquid chromatography-tandem mass spectrometry and free testosterone (FT) was calculated from TT and sex hormone-binding globulin (SHBG). Multivariable regression analyses were performed with HGS < 10th percentile as cutoff for low HGS.

RESULTS

Third-trimester FT concentration was 0.004 (0.002-0.007) nmol/L, geometric mean (mean - SD; mean + SD). The mean (SD) 5-year HGS was 8.7 (1.8) kg in boys and 8.1 (1.7) kg in girls (P < 0.001). Higher FT concentrations were associated with lower HGS (β = -0.186, P = 0.048), after adjustment for maternal age, parity, offspring sex, and 5-year height and weight. FT > 0.004 nmol/L was associated with higher risk of 5-year HGS < 10th percentile with odds ratios (95% CI) of 1.58 (1.01, 2.47; P = 0.047; n = 1,017) and 1.69 (1.05, 2.74; P = 0.032) after further adjustment for children's organized sports in subgroup analysis (n = 848). Lower HGS in relation to higher FT concentrations was found in all linear models but was not always statistically significant. HGS was not associated with maternal TT and SHBG levels.

CONCLUSION

Third trimester FT was inversely associated with offspring muscle strength assessed by HGS at 5 years of age, which may suggest a negative effect of maternal FT on offspring muscle strength.

Vitamin D Status and Health Outcomes in School Children in Northern Ireland: Year One Results from the D-VinCHI Study

(1) Background: Vitamin D status has never been investigated in children in Northern Ireland (UK). (2) Methods: Children (4-11 years) (n = 47) were recruited from November 2019 to March 2020 onto the cross-sectional study. Anthropometry was assessed. Plasma 25-hydroxyvitamin D (25(OH)D) was analysed. Vitamin D intake, parental knowledge and perceptions, participant habits, physical activity and sedentary behaviour were established via questionnaire. Muscle strength was assessed via isometric grip strength dynamometry and balance via dominant single-leg and tandem stance. Parathyroid hormone, bone turnover markers (OC, CTX and P1NP), glycated haemoglobin and inflammatory markers (CRP, IFN-γ, IL-10, IL-12p70, IL-13, IL-1β, IL-2, IL-4, IL-6, IL-8 and TNF-α) were analysed. (3) Results: Mean (SD) 25(OH)D was 49.17 (17.04) nmol/L (n = 47); 44.7% of the children were vitamin D sufficient (25(OH)D >50 nmol/L), 48.9% were insufficient (25-50 nmol/L) and 6.4% were deficient (<25 nmol/L). 25(OH)D was positively correlated with vitamin D intake (µg/day) (p = 0.012, r = 0.374), spring/summer outdoor hours (p = 0.006, r = 0.402) and dominant grip strength (kg) (p = 0.044, r = 0.317). Vitamin D sufficient participants had higher dietary vitamin D intake (µg/day) (p = 0.021), supplement intake (µg/day) (p = 0.028) and spring/summer outdoor hours (p = 0.015). (4) Conclusion: Over half of the children were vitamin D deficient or insufficient. Wintertime supplementation, the consumption of vitamin D rich foods and spring/summer outdoor activities should be encouraged to minimise the risk of vitamin D inadequacy.

The role of serum levels of vitamin D in children's muscle strength: A systematic review

This review aims to investigate the different levels of vitamin D and its role in muscle strength in healthy children and non-athletes. A search conducted in three databases (PubMed, Scopus, and Psycinfo) resulted in 655 articles, which were systematically analyzed and selected based on the following criteria: (a) original cross-sectional studies and clinical trials; (b) healthy children aged 5-11 years; (c) no language restriction or year of publication; and (d) studies that assessed the possible relationship between vitamin D levels and muscle strength. Six studies were included because they met all the inclusion criteria. According to the findings of this review, factors such as sex, skin color, and vitamin D supplementation early in life modulate the levels of vitamin D in the body, and there is a relationship between muscle strength and vitamin D levels. Interestingly, vitamin D supplementation is not always significantly associated with increased muscle grip strength. However, there is a scarcity of studies that aim to analyze the possible effects of different levels of vitamin D on muscle function and neuromuscular variables in physically inactive children and non-athletes without previously diagnosed disease. Further studies are warranted in the future to address the gap in the literature.

Association of serum 25-Hydroxyvitamin D with Vitamin D intervention and outdoor activity among children in North China: an observational study

Background

Living at high latitudes is one of the risk factors for vitamin D deficiency in children. However, evidence on vitamin D improvement for this pediatric population to date is limited. This study aims at evaluating the association of different vitamin D intervention methods and outdoor activity on the vitamin D status of children in North China.

Methods

In this observational study, a total of 55,925 children aged 1 month to 18 years old were recruited from pediatric outpatient departments from July 2016 to June 2017. Data on demographics, anthropometric measurements, vitamin D intervention (either prescribed by physicians or given by parents) and outdoor activity were recorded. The serum levels of 25-hydroxycholecalciferol (25(OH)D) were determined by high performance liquid chromatography tandem–mass spectrometry. Logistic regression analysis was performed to assess the association of vitamin D intervention or outdoor activity with blood vitamin D status, adjusted for age, gender, BMI for age, and seasons.

Results

The overall rate of hypovitaminosis D was 65.60%. Of the children’s outdoor activity, 35.63, 31.95, and 32.42% were below 30 min/d, 30–60 min/d and over 60 min/d, respectively. Furthermore, the proportion of therapeutic intervention, supplementation intervention and no vitamin D intervention among the children was 16.48, 32.87, and 50.65%, respectively. After adjusted for confounding factors, vitamin D intervention was associated with a lower risk of hypovitaminosis D, with OR (95% CI) of 0.191 (0.180, 0.202) in children with therapeutic doses and 0.423 (0.404, 0.443) in those with supplementation doses, compared with children without vitamin D intervention. In addition, longer outdoor time was associated with a lower risk of hypovitaminosis D [0.479 (0.456, 0.504) for 60 min/d, 0.737 (0.701, 0.776) for 30–60 min/d], independent of vitamin D intervention.

Conclusions

High prevalence of vitamin D deficiency was found in children living at high latitudes. Vitamin D intervention and outdoor activity are all negatively associated with children’s vitamin D deficiency. Routine vitamin D intervention combined with increased outdoor time might be an effective approach to prevent hypovitaminosis D among children, especially those at school, living at high latitudes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-020-02435-9.

Vitamin D status is associated with muscular strength in a nationally representative sample of US youth

AIM

To evaluate the association between serum 25-hydroxyvitamin D (25OHD) and muscular strength in a nationally representative sample of US youth.

METHODS

Participants (n = 3350) were 6- to 18-y-olds from 2011 to 2014 National Health and Nutrition Examination Survey. Relative handgrip strength was quantified using age- and sex-specific z-scores. Poor strength was defined as those <25th percentile. Multivariate general linear and logistic models were used to compare strength and poor strength status by clinically relevant groupings of 25OHD.

RESULTS

Approximately 20.2% of youth had 25OHD <50 nmol/L. Mean relative strength was highest for those at ≥75 nmol/L of 25OHD. The percentage of boys/girls with poor strength in the <50 nmol/L, 50-74.9 nmol/L and ≥75 nmol/L groups was 34.9%/32.3%, 25.8%/28.2% and 14.0%/15.8%, respectively. The odds of boys and girls with <50 nmol/L 25OHD having poor strength were 2.8 (95% CI: 1.4, 5.5) and 3.4 (1.7, 6.8) times higher compared to those with ≥75 nmol/L, respectively.

CONCLUSION

Higher levels of circulating vitamin D were associated with higher relative strength, and poor strength was more prevalent when 25OHD was <75 nmol/L. These findings highlight the value of vitamin D for the muscle-bone unit and potential extraskeletal ramifications.