Association between leisure-time aerobic physical activity and vitamin D concentrations among US older adults: the NHANES 2007-2012

The role of dietary intake of live microbes in the association between leisure-time physical activity and depressive symptoms: a population-based study

Current research has shown promising associations between factors such as diet, total physical activity, and mental health outcomes, acknowledging the intricate interplay between these variables. However, the role of dietary intake of live microbes, coupled with leisure-time physical activity (LTPA), in their relationship to depressive symptoms necessitates further exploration. The present study examined a cohort of 25 747 individuals who participated in the National Health and Nutrition Examination Survey between the years 2007 and 2018. Patient's Health Questionnaire (PHQ-9) was employed, whereby individuals scoring ≥ 10 were classified as exhibiting symptoms of depression. LTPA status was reported by the Global Physical Activity Questionnaire and calculated by metabolic equivalent-minutes/week. Foods consumed by participants were evaluated by live microbes per gram, which were categorized into three groups: low, medium, and high. After controlling for all covariates, findings indicated that LTPA was negatively associated with depressive symptoms (OR (95% confidence interval (CI): 0.983 (0.976, 0.990), p < 0.001). Participating in more LTPA was positively correlated with consuming all three levels of dietary live microbes (low, β (95% CI): 0.086 (0.063, 0.109); medium, β (95% CI): 0.009 (0.007, 0.012); high, β (95% CI): 0.002 (0.001, 0.002)). Moreover, taking more foods with medium live microbes was associated with lower depressive likelihood (OR (95% CI): 0.931(0.882, 0.982), p = 0.010). Intake of medium and high levels of live microbes mediated the association between LTPA and depressive symptoms by 4.15% and 0.83%, respectively. Dietary intake of foods containing medium and high levels of live microbes may be a mediator of LTPA's negative association with depressive symptoms.

The effect of physical activity on vitamin D: A systematic review and meta-analysis of intervention studies in humans

Objectives

Cross-sectional studies demonstrate a positive association between higher physical activity and serum 25-hydroxyvitamin D (25(OH)D) concentration. However, whether this association is causal is unclear. We conducted a systematic review to identify intervention studies that examined the effect of physical activity on serum 25(OH)D concentration in humans.

Study design

Systematic review and meta-analysis.

Methods

We searched PubMed, Scopus and Web of Science to identify full-text peer-reviewed articles published in English from inception until January 2023. Eligible studies were randomised controlled trials or quasi-experimental studies. We used random effects meta-analysis to calculate the weighted mean difference (WMD) in the change in 25(OH)D concentration between physical activity and control groups. We used the revised Cochrane risk-of-bias tool for randomized trials (RoB 2) to assess the methodological quality of included studies.

Results

We included 32 articles in the systematic review and 24 in the meta-analysis. The intervention varied from resistance and weight-bearing exercises (n = 13) to aerobic exercises (n = 10), moderate and moderate-to-vigorous exercises (n = 5), aquatic exercise (n = 2), and multicomponent traditional exercises (n = 2) (Tai Chi and Yijinjing). The WMD in 25(OH)D in the physical activity and control groups was 9.51 and 4.87, respectively (between-group mean difference 4.64, p = 0.002). However, the difference was only evident in studies that implemented the intervention outdoors (n = 3; between-group mean difference 17.33, p < 0.0001); when the intervention was indoors there was no significant effect of physical activity on 25(OH)D (n = 16; between-group mean difference 1.80, p = 0.113).

Conclusions

This meta-analysis of physical activity interventions in humans showed that physical activity does not lead to increased 25(OH)D independently of time outdoors. However, most studies were under-powered, in many the exercise was low intensity, and vitamin D was not the primary outcome.

Association of vitamin D and cognition in people with type 2 diabetes: a systematic review

CONTEXT

There is a high prevalence of vitamin D deficiency and impaired cognitive function in people with type 2 diabetes mellitus (T2DM).

OBJECTIVE

To critically and systematically review the literature on the association between vitamin D status and cognitive performance in people with type 2 diabetes.

DATA SOURCES

This review was conducted according to PRISMA recommendations. MEDLINE, SCOPUS, the Cochrane Library, and Web of Science databases were searched using the terms "Diabetes Mellitus, Type 2", "Cognitive Function", and "Vitamin D".

DATA EXTRACTION

Eight observational and 1 randomized study were included, containing data of 14 648 adult and elderly individuals (19-74 y). All extracted data were compiled, compared, and critically analyzed.

DATA ANALYSIS

There is no strong evidence that lower serum concentrations of vitamin D and vitamin D-binding protein are associated with worsening cognitive function in individuals with T2DM. Vitamin D supplementation (12 wk) improved the scores of some executive functioning tests, although there was no difference between low doses (5000 IU/wk) and high doses (50 000 IU/wk).

CONCLUSIONS

There is no high-quality evidence demonstrating an association between vitamin D status and cognitive function, or clinical benefits on cognition from vitamin D supplementation in individuals with T2DM. Future studies are needed. Systematic Review Registration: PROSPERO registration no. CRD42021261520.

Lack of significant seasonal association between serum 25(OH)D concentration, muscle mass and strength in postmenopausal women from the D-FINES longitudinal study

The aim of the present study was to assess the seasonal relationship between serum 25(OH)D concentration, lean mass and muscle strength. This was a secondary data analysis of a subgroup of 102 postmenopausal women participating in the 2006-2007 D-FINES (Vitamin D, Food Intake, Nutrition and Exposure to Sunlight in Southern England) study. The cohort was assessed as two age subgroups: <65 years (n=80) and ≥65 years (n=22). Outcome measures included lean mass (DXA), muscle strength (handgrip dynamometry) and serum 25(OH)D concentration (enzymeimmunoassay). Derived outcomes included appendicular skeletal muscle mass (ASM) and relative appendicular skeletal muscle index (RASM). Sarcopenia status was assessed using the European Working Group on Sarcopenia in Older People 2018 criteria. Non-parametric partial correlation using BMI as a covariate was used to evaluate the study aims. There were no statistically significant associations between total lean mass, ASM or RASM and 25(OH)D in any group at any season. There was a trend for handgrip strength to be positively associated with serum 25(OH)D concentration. There was a trend showing a higher prevalence of sarcopenia in women ≥65 years. Sarcopenia status appeared transient for five women. In conclusion, the present study found no significant association between vitamin D status and functional indicators of musculoskeletal health, which were additionally not affected by season.

Vitamin D Intake and Factors Associated With Self-Reported Vitamin D Deficiency Among US Adults: A 2021 Cross-Sectional Study

Vitamin D deficiency is a global issue that may be attributed to various factors such as dietary habits, sun exposure, age, race and chronic conditions. The purpose of this study was to determine the relationship between vitamin D intake from food/supplements and factors that may be associated with self-reported vitamin D deficiency among US adults. A cross-sectional online study was conducted among 1,637 adults using a 38-item questionnaire. Frequency counts and percentages were tabulated and a multiple linear regression was performed. Statistical significance was determined at p &lt; 0.05. Participants (n = 554, 33.8%) were considered vitamin D deficient and consumed an average of 347.05 ± 307.8 IUs of vitamin D through foods/beverages. The multivariate linear regression showed no statistically significant difference with vitamin D intake from foods/beverages on vitamin D deficiency status. Significant positive correlations were seen with vitamin D deficiency status and certain chronic conditions such as chronic kidney disease (p = 0.04), depression (p &lt; 0.001), diabetes (p = 0.02), and vitamin D supplement use (p &lt; 0.001). Significant negative correlations were observed with vitamin D deficiency status and age (p = 0.01) and sun exposure (p &lt; 0.001). Future focus should be on educating individuals about factors associated with vitamin D to reduce the prevalence of vitamin D deficiency.

Insulin Resistance and Vitamin D Deficiency: A Link Beyond the Appearances

Vitamin D is a steroid hormone that plays a key role in the regulation of body homeostasis, including cardiovascular function. Although the chronic deficiency of vitamin D is associated with cardiovascular risk factors, as well as with an adverse prognosis, randomized controlled trials have failed in demonstrating that dietary vitamin D supplementation could ameliorate the prognosis of patients with cardiovascular diseases, and suggested that vitamin D deficiency is the expression of the effects of other determinants of cardiovascular risk. Thus, the supplementation of vitamin D is not sufficient to improve the cardiovascular risk profile and prognosis. Insulin resistance is a complex phenomenon that plays a key role in the pathogenesis of conventional cardiovascular risk factors. Interestingly, defects of vitamin D and insulin resistance have a superimposable epidemiological distribution. According to the common view, Insulin resistance is considered the direct or indirect consequence of vitamin D deficiency. However, it is also reasonable to speculate that the deficit or the impaired action of vitamin D, in some circumstances, could be the result of the same pathogenic mechanisms responsible of insulin resistance development. In this case, vitamin D deficiency could be considered an epiphenomenon of insulin resistance. Insulin resistance is a reversible condition, being possibly ameliorated by physical activity and hypocaloric diets. Notably, both physical exercise and energy-restricted dietary regimens are associated with an increase of vitamin D levels. These findings indicate that improving insulin resistance condition is a necessary step to ameliorate vitamin D supplementation-based strategies in cardiovascular prevention.

Association of Sun-Protective Behaviors With Bone Mineral Density and Osteoporotic Bone Fractures in US Adults

Importance

Despite the reassuring emerging evidence on the lack of a causal relationship between sun protection and vitamin D deficiency, there is scarce data on whether multimodal sun protection is associated with reduced bone mineral density (BMD) and/or increased prevalence of osteoporotic bone fractures. This lack of data may lead to worry and decreased sun-protective behaviors on the part of patients.

Objective

To investigate the association of sun-protective behaviors with BMD z scores and the prevalence of osteoporotic fractures.

Design, Setting, and Participants

This population-based cross-sectional study included data from US adults who participated in the 2017 to 2018 cycle of the National Health and Nutrition Examination Survey (NHANES). Data were analyzed between September and November 2020.

Main Outcomes and Measures

Definition of sun-protective behaviors (staying in the shade, wearing long sleeves, and sunscreen use), site-specific and total BMD, and osteoporotic fractures (hip, wrist, and spine) in the NHANES data.

Results

Data from 3418 adults 20 years and older (average age, 39.5 [95% CI, 38.6-40.4] years; 1612 [47.2%] men and 1806 [52.9%] women) who completed the NHANES dermatology questionnaire were included in this study. The prevalence of frequent staying in the shade, wearing of long sleeves, and sunscreen use were 31.6% (95% CI, 27.8%-35.7%), 11.8% (95% CI, 10.6%-13.1%), and 26.1% (95% CI, 23.5%-28.8%), respectively. The use of individual sun-protective behaviors was not associated with diminished site-specific and total BMD z scores in the multivariate models (estimate, -0.23 [95% CI, -0.47 to 0.02], P = .18; -0.08 [-0.27 to 0.12], P = .72; and -0.10 [-0.32 to 0.13], P = .15 for frequent staying in the shade, wearing of long sleeves, and sunscreen use, respectively). Moderate to frequent staying in the shade was associated with reduced prevalence of spine fractures in the multivariate model (odds ratio, 0.19 [95% CI, 0.04-0.86], P = 0.02).

Conclusion and Relevance

In this cross-sectional study, routine use of sun-protective behaviors among the US adult population was not associated with decreased BMD or increased risk of osteoporotic fracture. Sun protection may be associated with a modest decrease in the prevalence of osteoporotic fractures, possibly owing to risk-averse behaviors. These reassuring findings add to the growing body of evidence on the safety of sun protection, with no considerable negative association with bone health.

Supplementation with a Natural Source of Amino Acids, Sil-Q1 (Silk Peptide), Enhances Natural Killer Cell Activity: A Redesigned Clinical Trial with a Reduced Supplementation Dose and Minimized Seasonal Effects in a Larger Population

The aim of this study was to re-validate the changes in natural killer (NK) cell cytotoxicity and cytokines related to T cells after Sil-Q1 (SQ; silk peptide) supplementation in a larger pool of Korean adults with minimized daily dose of SQ and controlling seasonal influence compared to the previous study. A total of 130 subjects were randomly assigned (1:1) to consume either 7.5 g of SQ or placebo for 8 weeks. NK cell cytotoxicity and cytokines were measured at T0 (baseline) and T8 (follow-up). Comparing the NK cell cytotoxicity values at T0 and T8 within each group, the cytotoxicity at all effector cell (E) to target cell (T) ratios of 10:1, 5:1, 2.5:1, and 1.25:1 was significantly increased in the SQ group at T8. Additionally, significant differences in the changed value (Δ, subtract baseline values from follow-up values) comparison between the groups at E:T = 10:1, 5:1, and 2.5:1 were found. As a secondary endpoint, the interleukin (IL)-12 level in the SQ group was significantly increased for 8 weeks, and Δ IL-12 in the SQ group was greater than in the placebo group. In conclusion, the present study showed considerable practical implications of SQ supplementation. Thus, SQ is an effective and safe functional food supplement for enhancing immune function.

Associations Between Lifestyle Factors and Reduced Kidney Function in US Older Adults: NHANES 1999-2016

Objective: This study aimed to evaluate the associations between lifestyle factors and the estimated glomerular filtration rate (eGFR) levels in older adults by analyzing the United States National Health and Nutrition Examination Survey data (1999–2016).

Methods: A total of 10,052 eligible participants were divided into two groups: reduced eGFR group (eGFR < 60 ml/min/1.73 m²) and normal group (eGFR ≥ 60 ml/min/1.73 m²). The primary factors were physical activity, alcohol consumption, smoking, and comorbidities.

Results: Multivariable analysis revealed that older age, proteinuria, cardiovascular disease, diabetes, hyperuricemia, and hypertension were significantly associated with higher odds of reduced kidney function. Sufficient physical activity, current alcohol consumption, and being a current smoker were significantly associated with lower odds of reduced kidney function. However, subgroup analysis by sex revealed that the effects of proteinuria, current alcohol consumption, and sufficient physical activity were sex-specific.

Conclusion: Several risk and beneficial factors for reduced kidney function in adults aged 65 and above in the United States were identified, but some of them might be sex-specific. Further studies are warranted to confirm these findings in other populations and countries.

U-shaped association of vigorous physical activity with risk of metabolic syndrome in men with low lean mass, and no interaction of physical activity and serum 25-hydroxyvitamin D with metabolic syndrome risk

BACKGROUND

There is uncertainty over how lean mass, physical activity (PA) and 25-hydroxyvitamin D (25-OH-D) status interact on metabolic syndrome (MetS) risk in adults.

AIMS

To test the hypothesis that these factors additively influence MetS risk.

METHODS

Four thousand eight hundred and fifty-eight adults (54.6% female) mean ± SD age 58.0 ± 5.8 years, body mass index 28.1 ± 4.8 kg/m² , resident in Busselton, Western Australia. PA assessed by questionnaire (all/total and vigorous), lean mass using dual energy X-ray absorptiometry (% total body mass), serum 25-OH-D via immunoassay, analysed using multivariable logistic regression.

RESULTS

In men, lower total PA was associated with MetS (no vs >24 h/week odds ratio (OR) = 3.1; ≤8 vs >24 h/week OR = 1.8, both P < 0.001), as was lower lean mass (low vs high OR = 20.4; medium vs high OR = 7.4, both P < 0.001). Men with low lean mass exhibited a U-shaped relationship of vigorous PA with MetS risk (covariate-adjusted: 0 vs 4-8 h/week OR = 2.1, P = 0.037; >12 vs 4-8 h/week OR = 4.3, P = 0.002; interaction P = 0.039). In women, low PA (0 vs >24 h/week OR = 2.1, P = 0.003) and lean mass (low vs high OR = 13.1; medium vs high OR = 7.2, both P < 0.001) were associated with MetS risk. Low 25-OH-D status was associated with MetS in men (low vs high OR = 4.1; medium vs high OR = 2.3, both P < 0.001) and women (OR = 3.5 and 2.1 respectively, both P < 0.001) with no PA interaction.

CONCLUSIONS

Men and women with high lean mass have low risk of MetS regardless of PA. Low lean mass identifies men who may benefit most from increasing PA, with an optimal level associated with lowest risk. 25-OH-D and PA do not interact on MetS risk.

Body weight changes and longitudinal associations with cognitive decline among community-dwelling older adults

INTRODUCTION

We aim to investigate the longitudinal associations between changes in body weight (BW) and declines in cognitive function and risk of mild cognitive impairment (MCI)/dementia among cognitively normal individuals 65 years or older.

METHODS

Data from the Age Gene/Environment Susceptibility-Reykjavik Study (AGES-Reykjavik Study) including 2620 participants, were examined using multiple logistic regression models. Cognitive function included speed of processing (SP), executive function (EF), and memory function (MF). Changes in BW were classified as; weight loss (WL), weight gain (WG), and stable weight (SW).

RESULTS

Mean follow-up time was 5.2 years and 61.3% were stable weight. Participants who experienced WL (13.4%) were significantly more likely to have declines in MF and SP compared to the SW group. Weight changes were not associated with EF. WL was associated with a higher risk of MCI, while WG (25.3%) was associated with a higher dementia risk, when compared to SW.

DISCUSSION

Significant BW changes in older adulthood may indicate impending changes in cognitive function.

Effects of High-Impact Weight-Bearing Exercise on Bone Mineral Density and Bone Metabolism in Middle-Aged Premenopausal Women: A Randomized Controlled Trial

This study examined the effects of high-impact weight-bearing exercise on bone mineral density (BMD) and bone metabolic markers in middle-aged premenopausal women. Forty middle-aged premenopausal women were initially enrolled, but thirty-one participants (40.34 ± 3.69 years) completed in the study. The subjects were randomly divided into two groups including the high-impact weight-bearing exercise group (HWE, n = 14) and control group (CON, n = 17). The HWE group participated in the exercise for 50 min a day, three days per week for four months, while the CON group maintained their regular lifestyle. The HWE program included 10 different high-impact weight-bearing exercises such as jumping and running. BMD was measured using DXA (Hologic, QDR 4500W, Marlborough, MA, USA). The bone metabolic markers including serum 25-(OH) D, intact parathyroid hormone (PTH), osteoprotegerin (OPG), osteopontin (OPN), receptor activator of nuclear factor κB ligand (RANKL), osteocalcin (OC), C-terminal telopeptide of type 1 collagen (CTX), and calcium were analyzed. The results showed that the BMDs of femur, lumbar, and forearm did not significantly change during the intervention period in both the HWE and CON groups. A significant decrease in bone formation markers such as OC (F = 10.514, p = 0.003, ηp2 = 0.266) and an increase in bone resorption marker including CTX (F = 8.768, p = 0.006, ηp2 = 0.232) were found only in the CON group, while these values did not change in the HWE group. There was a significant increase in serum 25-(OH) D (F = 4.451, p = 0.044, ηp2 = 0.133) in the HWE group. Our findings suggest that four months of HWE is not sufficient to improve BMD and bone metabolic markers, but this impact exercise program may prevent the age-associated changes in bone turnover markers in middle-aged premenopausal women.

Lifestyle and 25-hydroxy-vitamin D among community-dwelling old adults with dementia, mild cognitive impairment, or normal cognitive function

BACKGROUND

Several studies have indicated that older adults with cognitive impairment have a poorer lifestyle than their healthy peers including lower 25-hydroxy-vitamin D levels (25OHD).

AIM

To investigate the associations between lifestyle and 25OHD depending on cognitive status among old adults.

METHODS

Community-dwelling old adults (65-96 years) participated in this cross-sectional study based on the Age-Gene/Environment-Susceptibility-Reykjavik-Study. The analytical sample included 5162 subjects who were stratified by cognitive status, i.e., dementia (n = 307), mild cognitive impairment (MCI, n = 492), and normal cognitive status (NCS, n = 4363). Lifestyle variables were assessed and 25OHD was measured. The associations between lifestyle and 25OHD were calculated using linear models correcting for potential confounders.

RESULTS

According to linear regression models, 25OHD was significantly lower in older people with dementia (53.8 ± 19.6 nmol/L) than in NCS participants (57.6 ± 17.7 nmol/L). Cod liver oil (7.1-9.2 nmol/L, P < 0.001) and dietary supplements (4.4-11.5 nmol/L, P < 0.001) were associated with higher 25OHD in all three groups. However, physical activity ≥ 3 h/week (2.82 nmol/L, P < 0.001), BMI < 30 kg/m² (5.2 nmol/L, P < 0.001), non-smoking (4.8 nmol/L, P < 0.001), alcohol consumption (2.7 nmol/L, P < 0.001), and fatty fish consumption ≥ 3x/week (2.6 nmol/L, P < 0.001) were related to higher 25OHD in NCS only, but not in participants with dementia or MCI.

DISCUSSION

Older people living in Iceland with dementia are at higher risk for 25OHD deficiency when compared to healthy individuals. Physical activity reported among participants with dementia, and MCI is low and is not significantly associated with 25OHD.

CONCLUSIONS

Lifestyle factors among NCS participants are associated with 25OHD levels. Importantly, healthy lifestyle should be promoted among individuals with MCI and dementia.

The relationship between weight change history and 25(OH)D concentrations in adults

Introduction

Background: although obesity has been consistently associated with lower 25-OH hydroxyvitamin D-25(OH)D-levels, little is known about the effect of weight change on said 25(OH)D levels. Methods: the present analysis was based on data from the National Health and Nutrition Examination Survey. Percent weight changes were calculated from participant-reported maximum lifetime weight and weight in the past year and 10 years ago. Subsequently, general linear models adjusted for potential confounders were assembled to examine 25(OH)D concentrations across percent weight change categories. Results: a total of 6,237 participants with a mean age of 57.5 (SE, 0.2) years comprised the study sample. After adjustment for potential confounders, subjects who have gained weight ≥ 5 % in the past year and 10 years before had on average 4.5 and 5.1 nmol/L lower 25(OH)D levels than those with a stable weight, respectively. Moreover, this association persisted even among participants with adequate vitamin D intake. Notably, subjects who lost weight > 5 % from their maximum reported weight had significantly higher 25(OH)D levels than those who did not. Conclusion: subjects with a stable weight and those who lost weight ≥ 5% from their maximum reported lifetime weight had significantly higher 25(OH)D concentrations than those who did not. Thus, maintaining a healthy weight over time may be an effective strategy to reach optimal serum 25(OH)D levels.

Vitamin D Synthesis Following a Single Bout of Sun Exposure in Older and Younger Men and Women

Older adults are frequently cited as an at-risk population for vitamin D deficiency that may in part be due to decreased cutaneous synthesis, a potentially important source of cholecalciferol (vitamin D₃). Previous studies found that cutaneous D₃ production declines with age; however, most studies have been conducted ex vivo or in the photobiology lab. The purpose of this study was to characterize the response of vitamin D metabolites following a 30-min bout of sun exposure (15-min each to the dorsal and ventral sides) at close to solar noon in younger and older adults.

METHODS

30 healthy individuals with skin type II/III were recruited; a younger cohort, aged 20-37 (n = 18) and an older cohort (n = 12), age 51-69 years. Exposure was at outer limits of sensible sun exposure designed to enhance vitamin D synthesis without increasing risk of photo ageing and non-melanoma skin cancer. Serum D₃ concentration was measured at baseline, 24, 48 and 72 h post-exposure. Serum 25(OH)D was measured at baseline and 72 h post-exposure plus 168 h post-exposure in the older cohort.

RESULTS

D₃ increased in response to sun exposure (time effect; p = 0.002) with a trend for a difference in D₃ between cohorts (time*group; p = 0.09). By regression modeling of continuous data, age accounted for 20% of the variation in D₃ production. D₃ production decreased by 13% per decade. Despite changes in D₃, however, serum 25(OH)D did not change from baseline to 72 or 168 h post exposure (p > 0.10).

CONCLUSIONS

Serum D₃ concentration increased significantly in response to outdoor sun exposure in younger and older adults. While ageing may dampen cutaneous synthesis, sunlight exposure is still a significant source of vitamin D₃.

The Effect of Statins on Serum Vitamin D Concentrations Among Older Adults

Background Randomized and observational studies have previously reported inconsistent results for the direct association between statin therapy and 25, hydroxyvitamin D [25(OH)D] levels. Thus, the present study aimed to examine the relationship between statin use and 25(OH)D and its metabolites concentrations in a large nationally representative sample of older adults. Methods This study was conducted using data from the National Health and Nutrition Examination Survey. Participants were asked to show the medication containers of all the products used in the previous 30 days, and the prescription of statins was defined on the three-level nested therapeutic classification scheme of Cerner Multum's Lexicon. General linear models adjusted for potential confounders were created to compare 25(OH)D concentrations between older adults taking statins and those who did not.  Results A total of 6,261 participants with a mean age of 69.5 years comprised the study sample. Of those, 40.2% were taking statins with a median length of therapy of 5 years. Adjusted mean 25(OH)D3 and 25(OH)D levels were 3.3 and 4.4 nmol/L higher among participants taking statins than those who did not, respectively. Moreover, this association was consistently seen regardless of the duration of therapy and particularly in subjects taking simvastatin, atorvastatin, or rosuvastatin. In subgroup analyses according to BMI categories and vitamin D intake, higher 25(OH)D levels were also seen among statin users. By contrast, this association was attenuated among those with a daily vitamin D between 400 and 800 and >800 IU. Conclusion Older adults on statin therapy had significantly higher serum 25(OH)D concentrations. Additional research should be conducted to define the mechanism of this association and determine if the pleiotropic effects attributed to statins may be mediated by vitamin D.

The Prevalence and Determinants of Vitamin D Inadequacy among U.S. Older Adults: National Health and Nutrition Examination Survey 2007-2014

Background

Older adults (i.e., adults aged ≥ 60 years) are at higher risk of vitamin D deficiency compared to younger adults as a result of inadequate dietary vitamin D intake and limited exposure to sunlight. Thus, the present study aimed to describe the prevalence of vitamin deficiency and inadequacy among U.S. adults aged ≥ 60 years and the effect of vitamin D supplementation on 25, hydroxyvitamin D (25(OH)D) and its metabolites concentrations.

Methods

The present analysis was based on data from 6,261 participants in the National Health and Nutrition Examination Survey cycles 2007/2008 through 2013/2014. The prevalence of vitamin D deficiency and inadequacy was described according to demographic, behavioral, and health characteristics. Vitamin D deficiency was defined as 25(OH)D < 30 nmol/L; and vitamin D inadequacy was defined as < 50 nmol/L. Logistic regression models were assembled to examine the independent association of participants characteristics and the odds of having 25(OH)D inadequacy. Similarly, general linear models were used to assess the effect of vitamin D supplementation doses on 25(OH)D and its metabolites concentrations.

Results

The prevalence of 25(OH)D deficiency and inadequacy was 4.0% (standard error (SE), 0.4) and 17.4% (SE, 0.8), respectively. In general, the prevalence of 25(OH)D deficiency and inadequacy increased significantly among participants examined during the fall and winter months, women, non-Hispanic black patients, obese subjects, smokers, those physically inactive, and older adults with a daily vitamin D intake < 400 IU. After adjustment for potential confounders, subjects examined during the fall and winter months, females, non-Hispanic blacks, obesity, having a sedentary lifestyle, smokers, and a total vitamin D intake < 400 IU/day were variables significantly associated with increased odds of having vitamin D inadequacy. Notably, vitamin D supplement doses between 400 and 800 IU or > 800 IU/day were significantly correlated with higher 25(OH)D₃ concentrations considered as sufficient. 

Conclusion

25(OH)D inadequacy remains prevalent among U.S. older adults. Notably, optimal 25(OH)D₃ concentrations were consistently seen among vitamin D supplement users. Despite this finding, nearly half of the participants did not take vitamin D supplements. Thus, vitamin D supplementation should be considered an effective strategy to maintain adequate 25(OH)D status among older adults. 

The effects of calorie restriction, intermittent fasting and vegetarian diets on bone health

Uncountable health care organizations, clinicians, and individuals are striving to prevent obesity and the many chronic medical conditions linked to it by advocating a healthy lifestyle that includes measures such as reducing dietary calorie intake (i.e., calorie restriction = CR and intermittent fasting = IF) or limiting/abolishing animal source foods (i.e., practices termed vegetarianism and veganism). Although these regimens are traditionally considered healthy, their real impact on bone health has yet to be established, and some studies have reported that they have negative effects on bone outcomes. The current work provides an overview of the studies carried out to examine the effect/s of CR, IF and vegetarian/vegan diets on bone health, and, in particular, on bone mineral density (BMD) and fracture risk. Although data on this subject are limited to small studies and there is no information specifically referring to fractures, CR, but not IF, seems to reduce BMD but does not seem to affect bone quality. Vegetarian diets (particularly vegan ones) are associated with significantly lower BMD values with respect to omnivorous ones and could, potentially, increase the risk of fractures. Given these considerations, individuals who decide to follow these diets should be aware of the risk of osteoporosis and of bone fractures and should introduce dietary sources of calcium and Vitamin D and/or supplementation. Future studies examining fracture/osteoporosis incidence in selected populations will be able expand our knowledge about the safety of these diets and the risks linked to them.

Passive Commuting and Higher Sedentary Time Is Associated with Vitamin D Deficiency in Adult and Older Women: Results from Chilean National Health Survey 2016⁻2017

The aim was to investigate the associations between different physical activity (PA) patterns and sedentary time (ST) with vitamin D deficiency (<12 ng/mL) in a large sample of Chilean women. In this cross-sectional study, the final sample included 1245 adult and 686 older women. The PA levels, mode of commuting, ST, and leisure-time PA were self-reported. Vitamin D deficiency was defined as <12 ng/mL and insufficiency as <20 ng/mL. A higher ST was associated with vitamin D deficiency (odds ratio (OR): 2.4, 95%: 1.6⁻4.3) in adults, and passive commuting was associated with vitamin D deficiency in older (OR: 1.7, 95%: 1.1⁻2.7). Additionally, we found a joint association in the high ST/passive commuting group in adults (OR: 2.8, 95%: 1.6⁻4.9) and older (OR: 2.8, 95%: 1.5⁻5.2) with vitamin D deficiency, in respect to low ST/active commuting. The PA levels and leisure-time PA were not associated with vitamin D deficiency. In conclusion, mode of commuting and ST seems important variables related to vitamin D deficiency. Promoting a healthy lifestyle appears important also for vitamin D levels in adult and older women. Further studies are needed to establish causality of this association and the effect of vitamin D deficiency in different diseases in this population.