Serum 25-hydroxyvitamin D levels and incident diabetes mellitus type 2: a competing risk analysis in a large population-based cohort of older adults

Vitamin D and Risk of Incident Type 2 Diabetes in Older Adults: An Updated Systematic Review and Meta-Analysis

Vitamin D deficiency is very common worldwide, particularly in old age, when people are at the highest risk of the negative adverse consequences of hypovitaminosis D. Additionally to the recognized functions in the regulation of calcium absorption, bone remodeling, and bone growth, vitamin D plays a key role as a hormone, which is supported by various enzymatic, physiological, metabolic, and pathophysiological processes related to various human organs and systems. Accruing evidence supports that vitamin D plays a key role in pancreatic islet dysfunction and insulin resistance in type 2 diabetes. From an epidemiological viewpoint, numerous studies suggest that the growing incidence of type 2 diabetes in humans may be linked to the global trend of prevalent vitamin D insufficiency. In the past, this association has raised discussions due to the equivocal results, which lately have been more convincing of the true role of vitamin D supplementation in the prevention of incident type 2 diabetes. Most meta-analyses evaluating this role have been conducted in adults or young older persons (50-60 years old), with only one focusing on older populations, even if this is the population at greater risk of both hypovitaminosis D and type 2 diabetes. Therefore, we conducted an update of the previous systematic review and meta-analysis examining whether hypovitaminosis D (low serum 25OHD levels) can predict incident diabetes in prospective longitudinal studies among older adults. We found that low 25OHD was associated with incident diabetes in older adults even after adjusting for several relevant potential confounders, confirming and updating the results of the only previous meta-analysis conducted in 2017.

Vitamin D and Diabetic Kidney Disease

Vitamin D is a hormone involved in many physiological processes. Its active form, 1,25(OH)₂D₃, modulates serum calcium-phosphate homeostasis and skeletal homeostasis. A growing body of evidence has demonstrated the renoprotective effects of vitamin D. Vitamin D modulates endothelial function, is associated with podocyte preservation, regulates the renin-angiotensin-aldosterone system, and has anti-inflammatory effects. Diabetic kidney disease (DKD) is a leading cause of end-stage kidney disease worldwide. There are numerous studies supporting vitamin D as a renoprotector, potentially delaying the onset of DKD. This review summarizes the findings of current research on vitamin D and its role in DKD.

Longitudinal changes in vitamin D concentrations and the association with type 2 diabetes mellitus: the Tromsø Study

AIM

We aimed to investigate the relationship between pre- and post-diagnostic 25-hydroxyvitamin D (25(OH)D) concentrations and type 2 diabetes (T2DM) over a period of 30 years in individuals who developed T2DM compared to healthy controls.

METHODS

This case-control study included 254 participants with blood samples collected at five different time-points (T1-T5) between 1986 and 2016. Of the 254 participants, 116 were diagnosed with T2DM between T3 and T4, and were considered cases; the remaining 138 were controls. Linear mixed regression models were used to examine pre- and post-diagnostic changes in 25(OH)D concentrations, and logistic regression was used to examine associations between these concentrations and T2DM at each time-point.

RESULTS

25(OH)D concentrations at different time-points and the longitudinal change in concentrations differed between cases and controls, and by sex. For women, each 5-nmol/l increase in 25(OH)D concentrations was inversely associated with T2DM at T3 (odds-ratio, OR, 0.79), whereas for men, this same increase was positively associated with T2DM at T1 (OR 1.12). Cases experienced a significant decrease in pre-diagnostic 25(OH)D concentrations (p value < 0.01 for women, p value = 0.02 for men) and a significant increase in post-diagnostic 25(OH)D concentrations (p value < 0.01 for women, p value = 0.01 for men). As such, each 1-unit increase in month-specific z-score change between T1 and T3 was significantly inversely associated with T2DM (OR 0.51 for women, OR 0.52 for men), and each such increase between T3 and T5 was significantly positively associated with T2DM in women (OR 2.48).

CONCLUSIONS

25(OH)D concentrations seem to be affected by disease progression and type 2 diabetes diagnosis.

The modification of individual factors on association between serum 25(OH)D and incident type 2 diabetes: Results from a prospective cohort study

Several epidemiological studies have suggested an association between low vitamin D status and increased risk for type 2 diabetes (T2D). This study aimed to explore the dose-response relationship of serum 25-hydroxyvitamin D [25(OH)D] concentrations with incident T2D and the interaction between serum 25(OH)D with individual factors on T2D risk. A total of 1,926 adults without diabetes (mean age: 52.08 ± 13.82 years; 42% men) were prospectively followed for 36 months. Cox proportional hazards model and restricted cubic spline analysis were performed to assess the association and dose-response relationship between serum 25(OH)D and T2D incidence. Both additive and multiplicative interactions were calculated between serum 25(OH)D and individual factors. The net reclassification index (NRI) was used to evaluate the improvement of risk prediction of T2D by adding serum 25(OH)D to traditional risk factors. There were 114 new T2D cases over a mean follow-up of 36 months. Serum 25(OH)D was not associated with T2D incidence, and no significant dose-response relationship was found in the total population. However, stratified analyses suggested a non-linear inverse relationship among individuals with baseline fasting plasma glucose (FPG) <5.6 mmol/L (P _overall = 0.061, P _non-linear = 0.048). And a significant multiplicative interaction was observed between serum 25(OH)D and FPG on T2D risk (P = 0.005). In addition, we found a significant additive interaction of low serum 25(OH)D with older age (RERI = 0.897, 95% CI: 0.080-1.714; AP = 0.468, 95% CI: 0.054-0.881), male (AP = 0.441, 95% CI: 0.010-0.871), and insufficient physical activity (RERI = 0.875, 95% CI: 0.204-1.545; AP = 0.575, 95% CI: 0.039-1.111) on T2D risk. Significant additive interactions were also observed between vitamin D deficiency/insufficiency with male, overweight/obesity, and insufficient physical activity on T2D risk. Moreover, adding low serum 25(OH)D to a model containing established risk factors yielded significant improvements in the risk reclassification of T2D (NRI = 0.205, 95% CI: 0.019-0.391). Our results indicated a non-linear relationship of serum 25(OH)D concentrations with T2D risk among individuals with normal FPG and additive interactions of serum 25(OH)D with gender, overweight/obesity, and physical activity on T2D risk, suggesting the importance of outdoor exercise.

Clinical, metabolic, and immunological characterisation of adult Ugandan patients with new-onset diabetes and low vitamin D status

BACKGROUND

Low vitamin D concentrations are associated with metabolic derangements, notably insulin resistance and pancreatic beta-cell dysfunction in Caucasian populations. Studies on its association with the clinical, metabolic, and immunologic characteristics in black African adult populations with new-onset diabetes are limited. This study aimed to describe the clinical, metabolic, and immunologic characteristics of a black Ugandan adult population with recently diagnosed diabetes and hypovitaminosis D.

METHODS

Serum vitamin D concentrations were measured in 327 participants with recently diagnosed diabetes. Vitamin D deficiency, vitamin D insufficiency, and normal vitamin D status were defined as serum 25 hydroxyvitamin D levels of < 20 ng/ml, 21-29 ng/ml, and ≥ 30 ng/ml, respectively.

RESULTS

The median (IQR) age, glycated haemoglobin, and serum vitamin D concentration of the participants were 48 years (39-58), 11% (8-13) or 96 mmol/mol (67-115), and 24 ng/ml (18-30), respectively. Vitamin D deficiency, vitamin D insufficiency, and normal vitamin D status were noted in 105 participants (32.1%), 140 participants (42.8%), and 82 participants (25.1%), respectively. Compared with those having normal serum vitamin D levels, participants with vitamin D deficiency and insufficiency had higher circulating concentrations of interleukin (IL) 6 (29 [16-45] pg/ml, 23 [14-40] pg/ml vs 18 [14-32] pg/ml, p = 0.01), and IL-8 (24 [86-655] pg/ml, 207 [81-853] pg/ml vs 98 [67-224], p = 0.03). No statistically significant differences were noted in the markers of body adiposity, insulin resistance, and pancreatic beta-cell function between both groups.

CONCLUSION

Vitamin D deficiency and insufficiency were highly prevalent in our study population and were associated with increased circulating concentrations of pro-inflammatory cytokines. The absence of an association between pancreatic beta-cell function, insulin resistance, and low vitamin D status may indicate that the latter does not play a significant role in the pathogenesis of type 2 diabetes in our adult Ugandan population.

Vitamin D Deficiency Is Associated with Glycometabolic Changes in Nondiabetic Patients with Arterial Hypertension

Recent evidence indicates that mildly increased fasting and post-oral load blood glucose concentrations contribute to development of organ damage in nondiabetic patients with hypertension. In previous studies, vitamin D deficiency was associated with decreased glucose tolerance. The aim of this study was to examine the relationships between serum 25(OH)D levels and glucose tolerance and insulin sensitivity in hypertension. In 187 nondiabetic essential hypertensive patients free of cardiovascular or renal complications, we measured serum 25-hydroxyvitamin D (25(OH)D) and parathyroid hormone (PTH) and performed a standard oral glucose tolerance test (OGTT). Patients with 25(OH)D deficiency/insufficiency were older and had significantly higher blood pressure, fasting and post-OGTT (G-AUC) glucose levels, post-OGTT insulin (I-AUC), PTH levels, and prevalence of metabolic syndrome than patients with normal serum 25(OH)D. 25(OH)D levels were inversely correlated with age, blood pressure, fasting glucose, G-AUC, triglycerides, and serum calcium and PTH, while no significant relationships were found with body mass index (BMI), fasting insulin, I-AUC, HOMA index, and renal function. In a multivariate regression model, greater G-AUC was associated with lower 25(OH)D levels independently of BMI and seasonal vitamin D variations. Thus, in nondiabetic hypertensive patients, 25(OH)D deficiency/insufficiency could contribute to impaired glucose tolerance without directly affecting insulin sensitivity.

Combined associations of 25-hydroxivitamin D and parathyroid hormone with diabetes risk and associated comorbidities among U.S. white and black women

Background/objectives

There is evidence of black–white differences in vitamin D status and cardiometabolic health. This study aimed to further evaluate the joint associations of 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone (PTH) with risks of diabetes and related cardiometabolic comorbidities among white and black women.

Subjects/methods

We cross-sectionally and prospectively analyzed data from 1850 black and 3000 white postmenopausal women without cardiovascular disease or dialysis at baseline from the Women’s Health Initiative—Observational Study. Weighted Cox proportional hazards analyses and weighted logistic regression models were used to examine the joint associations of 25(OH)D and PTH with incident diabetes and prevalence of other diabetes-related cardiometabolic comorbidities (including CKD, hypertension, or obesity).

Results

We identified 3322 cases of obesity (n = 1629), hypertension (n = 2759), or CKD (n = 318) at baseline and 453 incident cases of diabetes during 11 years of follow-up. Cross-sectionally, lower 25(OH)D and higher PTH were independently associated with higher prevalence of hypertension [odds ratio (OR) = 0.79; 95% confidence interval (CI): 0.72–0.87 and OR = 1.55; 95% CI: 1.39–1.73] among white women only. When stratified by diabetes status, compared to women with 25(OH)D ≥50 nmol/L and PTH ≤6.89 pmol/L (65 pg/mL), women who did not have diabetes with vitamin D deficiency (<50 nmol/L) and PTH excess (>6.89 pmol/L) had higher prevalence of CKD, hypertension, or obesity (OR = 4.23; 95% CI: 2.90–6.18) than women who had diabetes (OR = 1.89; 95% CI: 0.96–3.71). Prospectively, lower 25(OH)D was associated with lower diabetes incidence [hazard ratio (HR) = 0.73; 95% CI: 0.62–0.86] in white women. Jointly, compared to the group with 25(OH)D ≥50 nmol/L and PTH ≤6.89 pmol/L, white women with 25(OH)D deficiency (<50 nmol/L) had elevated risk for diabetes, regardless of PTH levels.

Conclusions

Low 25(OH)D and high PTH were jointly associated with increased risk of diabetes among white women only. Their joint associations with high prevalence of CKD, hypertension, and obesity were more pronounced among women without diabetes.

Serum vitamin D levels in relation to type-2 diabetes and prediabetes in adults: a systematic review and dose-response meta-analysis of epidemiologic studies

BACKGROUND

Findings of observational studies that investigated the relationship between vitamin D deficiency and abnormal glucose homeostasis were contradictory. This meta-analysis of epidemiologic studies evaluated the association of vitamin D status and risk of type-2 diabetes (T2D) and prediabetes in adults.

METHODS

A systematic search was conducted on all published articles in five electronic databases (including MEDLINE/PubMed, EMBASE, Institute for Scientific Information, Scopus and Google scholar), up to August 2020. Twenty-eight prospective cohort and nested case-control studies and 83 cross-sectional and case-control investigations that reported relative risks (RRs) or odds ratios (ORs) with 95% confidence intervals (CIs) for abnormal glucose homeostasis in relation to serum vitamin D levels in adults were included in the analysis.

RESULTS

In prospective studies, high versus low level of vitamin D was respectively associated with significant 35%, 30% and 51% decrease in risk of T2D (RR:0.65; 95%CI: 0.55-0.76; 27 effect sizes), combined T2D and pre-diabetes (RR:0.70; 95%CI: 0.52-0.95; 9 effect sizes) and pre-diabetes (RR:0.49; 95%CI: 0.26-0.93; 2 effect sizes). These inverse associations were significant in almost all subgroups. Dose-response analysis in prospective studies showed that each 10 ng/ml increase in serum vitamin D levels resulted in 12% and 11% reduced risk of T2D (RR:0.88; 95%CI: 0.83-0.94) and combined T2D and prediabetes (RR:0.89; 95%CI: 0.87-0.92), respectively. In cross-sectional and case-control studies, highest versus lowest level of serum vitamin D was linked to reduced odds of T2D (OR:0.64; 95%CI: 0.57-0.72; 42 effect sizes) and combined T2D and pre-diabetes (OR:0.79; 95%CI: 0.74-0.85; 59 effect sizes); but not pre-diabetes (OR:0.64; 95%CI: 0.17-2.37; 11 effect sizes).

CONCLUSION

This meta-analysis of epidemiologic studies disclosed that serum vitamin D level was reversely associated with the risk of T2D and combined T2D and prediabetes in adults, in a dose-response manner. However, the association was not remarkable for pre-diabetes.

Serum 25-Hydroxyvitamin D, Albumin, and Mortality Among Chinese Older Adults: A Population-based Longitudinal Study

CONTEXT

The associations between serum 25-hydroxyvitamin D concentrations [25(OH)D] and all-cause mortality have been inconsistent in existing literatures. One plausible reason is the interaction of intrinsic vitamin D with other biological conditions such as malnutrition and chronic inflammation.

OBJECTIVE

To explore the associations between serum levels of 25(OH)D, albumin, and all-cause mortality and further evaluate their interactions in elderly people.

DESIGN

Population-based longitudinal study.

SETTING AND PARTICIPANTS

Data were obtained from 1834 people aged 65 to 112 who had their serum 25(OH)D and albumin assayed at baseline in 2011. Participants' survival status was ascertained at the 2014 and 2018 follow-up survey waves.

MAIN OUTCOME MEASURES

All-cause mortality.

RESULTS

Among the 1834 participants, both serum 25(OH)D and albumin concentrations were inversely associated with all-cause mortality (Ps < 0.001). In addition, the interaction effect of 25(OH)D and albumin on all-cause mortality was observed among the participants (P = 0.001). In the group with a higher albumin level (≥40 g/L), participants with a lower level of 25(OH)D (<50 nmol/L) had higher risk of mortality than their counterparts (hazard ratio, 1.92; 95% confidence interval, 1.45-2.56), and the association was more pronounced in women. In the group with a lower albumin level (<40 g/L), the associations failed to reach statistical significance in all participants as well as in women and in men.

CONCLUSIONS

Serum 25(OH)D and albumin levels were inversely associated with all-cause mortality in Chinese older adults. The association between 25(OH)D and mortality was more pronounced in participants with higher albumin levels.

Low Vitamin D Levels and Frailty Status in Older Adults: A Systematic Review and Meta-Analysis

Serum vitamin D deficiency is widespread among older adults and is a potential modifiable risk factor for frailty. Moreover, frailty has been suggested as an intermediate step in the association between low levels of vitamin D and mortality. Hence, we conducted a systematic review of the literature and meta-analysis to test the possible association of low concentrations of serum 25-hydroxyvitamin D (25(OH)D), a marker of vitamin D status, with frailty in later life. We reviewed cross-sectional or longitudinal studies evaluating populations of older adults and identifying frailty by a currently validated scale. Meta-analyses were restricted to cross-sectional data from studies using Fried’s phenotype to identify frailty. Twenty-six studies were considered in the qualitative synthesis, and thirteen studies were included in the meta-analyses. Quantitative analyses showed significant differences in the comparisons of frail (standardized mean difference (SMD)—1.31, 95% confidence interval (CI) (−2.47, −0.15), p = 0.0271) and pre-frail (SMD—0.79, 95% CI (−1.58, −0.003), p = 0.0491) subjects vs. non-frail subjects. Sensitivity analyses reduced heterogeneity, resulting in a smaller but still highly significant between-groups difference. Results obtained indicate that lower 25(OH)D levels are significantly associated with increasing frailty severity. Future challenges include interventional studies testing the possible benefits of vitamin D supplementation in older adults to prevent/palliate frailty and its associated outcomes.

Association of Hypovitaminosis D with Metabolic Syndrome in Postmenopausal Women

The prevalence of vitamin D deficiency and metabolic syndrome is spreading like a pandemic globally; postmenopausal women are particularly vulnerable population. Hypovitaminosis D is reported to predispose to various components of metabolic syndrome like dyslipidemia, hypertension, diabetes and obesity. The purpose of this review is to highlight the recently published evidence, evaluating the association of vitamin D deficiency with metabolic syndrome in postmenopausal women. Besides, it emphasizes the long-term risks involved with low vitamin D levels and importance of vitamin D supplementation. Data were obtained from PubMed, Google Scholar and individual searches.

Association Between Serum Magnesium and the Prevalence of Kidney Stones: a Cross-sectional Study

Kidney stones, a painful and costly disease, have become a public health problem worldwide. The aim of this study was to evaluate the association between serum magnesium levels and the prevalence of kidney stones in a large population context. This study was conducted in Xiangya Hospital, Central South University in Changsha, Hunan, China, between October 2013 and December 2015. A total of 6228 subjects aged ≥ 18 years old were included. Kidney stones were diagnosed by (1) direct visualisation of stone(s) on the abdominal ultrasound examination, and (2) presence of stone(s) with a diameter ≥ 4 mm. The chemiluminescence method was used to measure the serum magnesium concentration. The association between serum magnesium and the prevalence of kidney stones was evaluated using logistic and spline regression in a cross-sectional study. The prevalence of kidney stones was 6.1% (7.5% in men and 4.2% in women). Compared with the lowest quartile, the crude odds ratio for kidney stones was 0.62 (95% CI 0.46-0.85) for the highest quartile of serum magnesium, and there was an inverse dose-response relationship (P for trend = 0.038). Similar results were observed for men and women separately. The findings were not materially altered by adjustment for potential confounders. In conclusion, subjects with relatively lower levels of serum magnesium, even though within the normal range, were subject to a higher prevalence of kidney stones in a dose-response relationship manner, indicating that magnesium may play a certain role in the prevention or treatment of kidney stones.

Oxidatively Damaged DNA/RNA and 8-Isoprostane Levels Are Associated With the Development of Type 2 Diabetes at Older Age: Results From a Large Cohort Study

OBJECTIVE

Oxidative stress is believed to play an important role in the pathophysiology of type 2 diabetes, but the few cohort studies that have assessed the association of oxidative stress biomarkers with type 2 diabetes incidence were small and reported inconclusive results.

RESEARCH DESIGN AND METHODS

We examined the associations of urinary oxidized guanine/guanosine (OxGua) levels (a biomarker of DNA/RNA oxidation) and urinary 8-isoprostane levels (a biomarker of lipid peroxidation) with type 2 diabetes incidence in 7,828 individuals initially without diabetes from a population-based German cohort study with 14 years of follow-up. Hazard ratios (HRs) (95% CIs) per 1 SD were obtained using multivariable-adjusted Cox proportional hazards regression models.

RESULTS

In the total population, weak but statistically significant associations with type 2 diabetes incidence were observed for OxGua levels (HR [95% CI] per 1 SD 1.05 [1.01; 1.09]) and 8-isoprostane levels (1.04 [1.00; 1.09]). Stratified analyses showed that associations of both biomarkers with type 2 diabetes incidence were absent in the youngest age-group (50-59 years) and strongest in the oldest age-group (65-75 years) of the cohort, with HR of OxGua levels 1.14 (1.05; 1.23) per 1 SD and of 8-isoprostane levels 1.22 (1.02; 1.45) per 1 SD.

CONCLUSIONS

These results from a large cohort study support suggestions that an imbalanced redox system contributes to the development of type 2 diabetes but suggest that this association becomes clinically apparent at older ages only, possibly as a result of reduced cellular repair capacity.

Association between dietary selenium intake and the prevalence of osteoporosis: a cross-sectional study

Objective

To examine the correlation between dietary selenium (Se) intake and the prevalence of osteoporosis (OP) in the general middle-aged and older population in China.

Methods

Data for analyses were collected from a population based cross-sectional study performed at the Xiangya Hospital Health Management Centre. Dietary Se intake was evaluated using a validated semi-quantitative food frequency questionnaire. OP was diagnosed on the basis of bone mineral density scans using a compact radiographic absorptiometry system. The correlation between dietary Se intake and the prevalence of OP was primarily examined by multivariable logistic regression.

Results

This cross-sectional study included a total of 6267 subjects (mean age: 52.2 ± 7.4 years; 42% women), and the prevalence of OP among the included subjects was 9.6% (2.3% in men and 19.7% in women). Compared with the lowest quartile, the energy intake, age, gender and body mass index (BMI)-adjusted odds ratios of OP were 0.72 (95% confidence interval [CI] 0.55–0.94), 0.72 (95% CI 0.51–1.01) and 0.47 (95% CI 0.31–0.73) for the second, third and fourth quartiles of dietary Se intake, respectively (P for trend = 0.001). The results remained consistent in male and female subjects. Adjustment for additional potential confounders (i.e., smoking status, drinking status, physical activity level, nutritional supplements, diabetes, hypertension, fibre intake, and calcium intake) did not cause substantial changes to the results.

Conclusions

In the middle-aged and older humans, participants with lower levels of dietary Se intake have a higher prevalence of OP in a dose-response manner.

Association between dietary iron intake and the prevalence of nonalcoholic fatty liver disease: A cross-sectional study

The aim was to test the association between dietary iron intake and the prevalence of nonalcoholic fatty liver disease (NAFLD) in a large sample of middle-aged and elderly Chinese population.The data included in this analysis were collected from a population-based cross-sectional study, that is, the Xiangya Hospital Health Management Center Study. Dietary iron intake was assessed using a validated semiquantitative food frequency questionnaire. The relationship between dietary iron intake and the prevalence of NAFLD was examined using logistic and spline regressions.A cross-sectional study including 5445 subjects was conducted. The prevalence of NAFLD was 36.9%. Compared with the lowest quintile, the energy-adjusted odds ratios (ORs) of NAFLD were 1.33 (95% confidence interval [CI]: 1.07-1.64), 1.80 (95% CI: 1.41-2.29) and 2.11 (95% CI: 1.60-2.80) in the 3rd, 4th, and 5th quintile of iron intake, respectively (P-value for trend <.001). In addition, dietary iron intake was positively associated with the OR of NAFLD in a dose-response relationship manner (test for trend P < .001). However, after stratifying the data by gender, such association only remained in the male, but not in the female population. With adjustment of additional potential confounders, the results did not change materially.Subjects with higher dietary iron intake were subject to a higher prevalence of NAFLD in a dose-response relationship manner. However, such association probably only exists in males, but not in females.

Role of Vitamin D Status in Diabetic Patients with Renal Disease

Diabetes mellitus (DM) poses a major public health problem worldwide, with ever-increasing incidence and prevalence in recent years. The Institute for Alternative Futures (IAF) expects that the total number of people with type 1 and type 2 DM in the United States will increase by 54%, from 19,629,000 to 54,913,000 people, between 2015 and 2030. Diabetic Nephropathy (DN) affects about one-third of patients with DM and currently ranks as the first cause of end-stage kidney disease in the Western world. The complexity of interactions of Vitamin D is directly related with progressive long-term changes implicated in the worsening of renal function. These changes result in a dysregulation of the vitamin D-dependent pathways. Various studies demonstrated a pivotal role of Vitamin D supplementation in regression of albuminuria and glomerulosclerosis, contrasting the increase of glomerular basement membrane thickening and podocyte effacement, with better renal and cardiovascular outcomes. The homeostasis and regulation of the nephron’s function are absolutely dependent from the cross-talk between endothelium and podocytes. Even if growing evidence proves that vitamin D may have antiproteinuric, anti-inflammatory and renoprotective effects in patients with DN, it is still worth investigating these aspects with both more in vitro studies and randomized controlled trials in larger patient series and with adequate follow-up to confirm the effects of long-term vitamin D analogue supplementation in DN and to evaluate the effectiveness of this therapy and the appropriate dosage.

25-Hydroxyvitamin D and the risk of incident diabetes in Hong Kong Chinese

OBJECTIVE

To investigate the relationship between serum 25-hydroxyvitamin D (25(OH)D) and risk of incident diabetes in Hong Kong Chinese, after accounting for the effect of multiple bone- and mineral-related markers.

DESIGN

We conducted a retrospective study on the Hong Kong Osteoporosis Study cohort. Incident diabetes was ascertained using electronic medical records. Serum 25(OH)D was measured at baseline and its association with incident diabetes was evaluated using multivariable Cox proportional-hazard regression.

PARTICIPANTS

Individuals (n 4342) aged 20 years or above (1395 men, 2947 women; mean age 54·3 (sd 16·5) years) from the Hong Kong Osteoporosis Study, who were free of diabetes at baseline, were included.

RESULTS

During 40 124·7 person-years of follow-up (a median of 9·2 years), 443 participants developed diabetes. Mean 25(OH)D was 63·34 (sd 13·07) nmol/l. Age-, sex- and BMI-adjusted Cox proportional-hazard regression showed no significant difference in the risk of incident diabetes between the lowest and the highest quintiles of 25(OH)D. In the analysis of the interaction effect between 25(OH)D and serum Ca, the interaction term did not affect the risk of incident diabetes significantly (P = 0·694). Similarly, there was no significant interaction of different subgroups (age, sex, BMI, femoral-neck T-score, serum Ca levels) with serum 25(OH)D.

CONCLUSIONS

The present study finds that serum vitamin D level is not associated with the risk of incident diabetes in Hong Kong Chinese and this relationship is not modified by serum Ca level.

Association Between Dietary Selenium Intake and the Prevalence of Nonalcoholic Fatty Liver Disease: A Cross-Sectional Study

Objective: The aim was to examine the association between dietary selenium intake and nonalcoholic fatty liver disease (NAFLD) in a large group of middle-aged and elderly Chinese persons.Method: The data included in this analysis were from a population-based study, the Xiangya Hospital Health Management Center Study. NAFLD was diagnosed by (1) imaging or histological evidence of hepatic steatosis; (2) absence of specific etiologies of NAFLD; and (3) no heavy consumption of alcohol. Dietary selenium intake was assessed using a validated semi-quantitative food frequency questionnaire. The association between dietary selenium intake and the prevalence of NAFLD was evaluated using logistic and spline regression in a cross-sectional study of 5436 subjects.Results: The prevalence of NAFLD was 36.8%. Compared with the lowest quintile, the energy-adjusted odds ratios for NAFLD were 1.27 (95% confidence interval [CI], 1.07-1.52), 1.30 (95% CI, 1.09-1.55), and 1.58 (95% CI, 1.33-1.89) for the third, fourth, and fifth quintiles of selenium intake, respectively, and there was a positive dose-response relationship (r = 0.88, p for trend = 0.008). Similar results were observed for men and women separately. The findings were not materially altered by adjustment for potential confounders (i.e., age, gender, body mass index, smoking status, diabetes, hypertension, activity level, nutritional supplements, energy intake, fat intake, fiber intake, cholesterol and saturated fatty acid intake).Conclusions: In this middle-aged and elderly population, subjects with higher dietary selenium intake, even below the recommended nutrient intake in China, had higher prevalence of NAFLD in a dose-response relationship manner.

Preoperative Serum 25-Hydroxyvitamin D Level, a Risk Factor for Postoperative Cognitive Dysfunction in Elderly Subjects Undergoing Total Joint Arthroplasty

BACKGROUND

Postoperative cognitive dysfunction (POCD) is a very common postoperative complication occurring mainly after high-risk surgery, especially in the elderly individuals. This study aimed to investigate potential risk factors for POCD in elderly patients after total joint arthroplasty (TJA).

MATERIALS AND METHODS

A total of 257 eligible elderly patients (≥65 years) who were scheduled for elective TJA for osteoarthritis with general anesthesia were enrolled. An experienced psychiatrist was invited to evaluate the cognitive function at baseline (1 day before the surgery) and at day 7 after the surgery. Univariate and multiple logistic regression analyses were performed to screen risk factors associated with POCD. Receiver-operating characteristic curve analysis was performed to assess the predictive value of serum 25-hydroxyvitamin D [25(OH)D] expression for POCD.

RESULTS

Of all the 257 enrolled patients, 55 (21.4%) developed POCD within 7 days after the surgery. Serum 25(OH)D level was the only independent risk factor associated with POCD (odds ratio: 1.77, 95% confidence interval: 1.13-2.78, P = 0.016) by multiple logistic regression analysis. The area under the curve of 25(OH)D for POCD was 0.687, with the cut-off value of 11.2 ng/mL, sensitivity of 41.82% and specificity of 78.71% respectively (95% confidence interval: 0.617-0.757, P < 0.001).

CONCLUSIONS

Our results revealed that preoperative serum 25(OH)D level was an independent risk factor for POCD in elderly subjects after TJA.

Preoperative vitamin D deficiency increases the risk of postoperative cognitive dysfunction: a predefined exploratory sub-analysis

BACKGROUND

Vitamin D is important for maintaining physiological functions including cognition and its deficiency is associated with the occurrence of cognitive impairment. This study was to explore the association between preoperative vitamin D status and the occurrence of postoperative cognitive dysfunction (POCD) in elderly patients undergoing major surgery.

METHODS

This was a predefined exploratory sub-analysis of one-centre data from a randomized controlled trial. In all, 123 elderly (≥ 65 years) patients who were scheduled to undergo major cancer surgery were recruited. Serum 25-hydroxyvitamin D concentration was measured before surgery. In total, 59 nonsurgical control subjects with comparable age and education level were also enrolled. A battery of neuropsychological tests was administered the day before and the 7th day after surgery in patients or at the same time interval in control subjects. POCD was diagnosed according to the ISPOCD1 definition.

RESULTS

71.5% (88/123) of elderly patients had vitamin D deficiency (serum 25-hydroxyvitamin D concentration < 12 ng/ml) before surgery; 24.4% (30/123) of them developed cognitive dysfunction at 1 week after surgery. After adjusting for confounding factors, high preoperative serum 25-hydroxyvitamine D concentration was related to a decreased risk of POCD (odds ratio [OR]: 0.829, 95% confidence interval [CI]: 0.708-0.971; P = 0.020), whereas preoperative vitamin D deficiency was associated with an increased risk of POCD (OR: 8.427, 95% CI: 1.595-44.511; P = 0.012).

CONCLUSIONS

Vitamin D deficiency is prevalent in elderly patients undergoing major cancer surgery and increases the risk of early POCD development. Whether prophylactic vitamin D supplementation can reduce POCD in the elderly deserves further study.

Review on Potential Vitamin D Mechanism with Type 2 Diabetes Mellitus Pathophysiology in Malaysia

Evidences on vitamin D deficiency suggest there is increasing risk of diabetes. To date, some cohort, observation, cross-sectional studies on populations and randomized controlled trials in vitamin D supplements highlighting the potential of vitamin D are essentially in modifying Type 2 Diabetes Mellitus (T2DM) pathophysiology. Relevant literature sought in a various databases focus on the discovery of vitamin D studies in Malaysia, particularly in dietary, health status and disease study. However, recent data in Malaysia, the scope of the literature focuses on the deficient vitamin D mediated insulin impairment. The development of literary findings encompasses on the etiology of diabetes which highly correlates with decreased mechanism of action of vitamin D. It is important to understand diabetes etiology before explaining more about insulin resistance mechanisms which is strongly correlated with the involvement of c-Jun N-terminal kinase (JNK) pathways in insulin signalling. Furthermore, the vitamin D works synergistically with calcium homeostasis which is believed to have interaction with insulin. The purpose of this article is to illustrate the potential of vitamin D in modulating T2DM pathophysiology. Existing evidence showing the biochemical function of vitamin D is strongly involved in the pathogenesis of T2DM which requires considerable attention.

Plasma 25-hydroxyvitamin D concentration and risk of type 2 diabetes and pre-diabetes: 12-year cohort study

BACKGROUND

It has been reported that higher plasma 25-hydroxyvitamin D is associated with lower risk of type 2 diabetes. However the results to date have been mixed and no adequate data based on a cohort are available for the high end of the normal range, above approximately 32 ng/ml or 80 nmol/L.

METHODS

We performed a cohort study of 903 adults who were known to be free of diabetes or pre-diabetes during a 1997-1999 visit to a NIH Lipid Research Centers clinic. Plasma 25(OH)D was measured at Visit 8 in 1977-1979. The mean age was 74 years. The visit also included fasting plasma glucose and oral glucose tolerance testing. Follow-up continued through 2009.

RESULTS

There were 47 cases of diabetes and 337 cases of pre-diabetes. Higher 25(OH)D concentrations (> 30 ng/ml) were associated with lower hazard ratios (HR) for diabetes: 30-39 ng/ml or 75-98 nmol/L: HR = 0.31, 95% CI = 0.14-0.70; for 40-49 ng/ml or 100-122 nmol/L: HR = 0.29, CI = 0.12-0.68; for > 50 ng/ml or 125 nmol/L: HR = 0.19, CI = 0.06-0.56. All HRs are compared to < 30 ng/ml or 75 nmol/L. There was an inverse dose-response gradient between 25(OH)D concentration and risk of diabetes with a p for trend of 0.005. Each 10 ng/mL or 25 nmol/L higher 25(OH)D concentration was associated with a HR of 0.64, CI = 0.48-0.86. 25(OH)D concentrations were more weakly inversely associated with pre-diabetes risk, and the trend was not significant.

CONCLUSION

Further research is needed on whether high 25(OH)D might prevent type 2 diabetes or transition of prediabetes to diabetes.

Associations of vitamin D with insulin resistance, obesity, type 2 diabetes, and metabolic syndrome

The aim of this study is to determine the relationships of vitamin D with diabetes, insulin resistance obesity, and metabolic syndrome. Intra cellular vitamin D receptors and the 1-α hydroxylase enzyme are distributed ubiquitously in all tissues suggesting a multitude of functions of vitamin D. It plays an indirect but an important role in carbohydrate and lipid metabolism as reflected by its association with type 2 diabetes (T2D), metabolic syndrome, insulin secretion, insulin resistance, polycystic ovarian syndrome, and obesity. Peer-reviewed papers, related to the topic were extracted using key words, from PubMed, Medline, and other research databases. Correlations of vitamin D with diabetes, insulin resistance and metabolic syndrome were examined for this evidence-based review. In addition to the well-studied musculoskeletal effects, vitamin D decreases the insulin resistance, severity of T2D, prediabetes, metabolic syndrome, inflammation, and autoimmunity. Vitamin D exerts autocrine and paracrine effects such as direct intra-cellular effects via its receptors and the local production of 1,25(OH)₂D₃, especially in muscle and pancreatic β-cells. It also regulates calcium homeostasis and calcium flux through cell membranes, and activation of a cascade of key enzymes and cofactors associated with metabolic pathways. Cross-sectional, observational, and ecological studies reported inverse correlations between vitamin D status with hyperglycemia and glycemic control in patients with T2D, decrease the rate of conversion of prediabetes to diabetes, and obesity. However, no firm conclusions can be drawn from current studies, because (A) studies were underpowered; (B) few were designed for glycemic outcomes, (C) the minimum (or median) serum 25(OH) D levels achieved are not measured or reported; (D) most did not report the use of diabetes medications; (E) some trials used too little (F) others used too large, unphysiological and infrequent doses of vitamin D; and (G) relative paucity of rigorous clinical data on the effects of vitamin D sufficiency on non-calcium endpoints. Although a large number of observational studies support improving T2D, insulin resistance, obesity, and metabolic syndrome with vitamin D adequacy, there is a lack of conclusive evidence from randomized control clinical trials that, these disorders are prevented following optimization of serum levels of 25(OH)D. However, none of the currently conducted clinical studies would resolve these issues. Thus, specifically designed, new clinical studies are needed to be conducted in well-defined populations, following normalizing the serum vitamin D levels in vitamin D deficient prediabetes subjects, to test the hypothesis that hypovitaminosis D worsens these disorders and correction would alleviate it.

Retracted: Serum 25-hydroxyvitamin D and risk of type 2 diabetes in older adults: A dose-response meta-analysis of prospective cohort studies

Lower serum level of 25-hydroxyvitamin D is common in older adults and associated with several negative outcomes. However, previous studies have indicated that 25-hydroxyvitamin D is associated with risk of type 2 diabetes, but presented controversial results.Studies in PubMed and EMBASE were searched update to June 2017 to identify and quantify the potential dose-response association between low 25-hydroxyvitamin D and risk of type 2 diabetes in older adults.Nine eligible studies involving a total of 34,511 participants with 2863 incident cases were included in this meta-analysis. Our results showed statistically significant association between lower 25-hydroxyvitamin D and type 2 diabetes in older adults [odds ratio (OR) = 1.19, 95% confidence interval (95% CI): 1.08-1.32, P = .001]. In addition, we obtained the best fit at an inflection point of decrease 10 ng/mL in piecewise regression analysis; the summary relative risk of type 2 diabetes in older adults for a decrease of 10 ng/mL 25-hydroxyvitamin D was 1.06 (95% CI: 1.02-1.13, P < .001). Furthermore, subgroups analysis indicated that lower 25-hydroxyvitamin D was associated with a significant increment risk of type 2 diabetes in older adults in female (OR = 1.21, 95% CI: 1.04-1.40, P = .014) but not in male (OR = 1.11, 95% CI: 0.75-1.63, P = .615). Subgroup meta-analyses in study design, duration of follow-up, number of participants, and number of cases showed consistent with the primary findings.Lower 25-hydroxyvitamin D is associated with type 2 diabetes in older adults risk increment.

1α,25-Dihydroxyvitamin D3 promotes bone formation by promoting nuclear exclusion of the FoxO1 transcription factor in diabetic mice

1α,25-Dihydroxyvitamin D3 (1,25(OH)2D3) is the active form of vitamin D, which is responsible for reducing the risk for diabetes mellitus (DM), decreasing insulin resistance, and improving insulin secretion. Previous studies have shown that 1,25(OH)2D3 inhibited the activity of FoxO1, which has been implicated in the regulation of glucose metabolism. However, its function and mechanism of action in DM-induced energy disorders and also in bone development remains unclear. Here, using in vitro and in vivo approaches including osteoblast-specific, conditional FoxO1-knock-out mice, we demonstrate that 1,25(OH)2D3 ameliorates abnormal osteoblast proliferation in DM-induced oxidative stress conditions and rescues the impaired glucose and bone metabolism through FoxO1 nuclear exclusion resulting from the activation of PI3K/Akt signaling. Using alizarin red staining, alkaline phosphatase assay, Western blot, and real-time qPCR techniques, we found that 1,25(OH)2D3 promotes osteoblast differentiation and expression of osteogenic phenotypic markers (i.e. alkaline phosphatase (1), collagen 1 (COL-1), osteocalcin (OCN), and osteopontin (OPN)) in a high-glucose environment. Moreover, 1,25(OH)2D3 increased both total OCN secretion and levels of uncarboxylated OCN (GluOC) by phosphorylating FoxO1 and promoting its nuclear exclusion, indicated by Western blot and cell immunofluorescence analyses. Taken together, our findings confirm that FoxO1 is a key mediator involved in glucose homeostasis and indicate that 1,25(OH)2D3 improves glucose metabolism and bone development via regulation of PI3K/Akt/FoxO1/OCN pathway.

Dose-response relationship between lower serum magnesium level and higher prevalence of knee chondrocalcinosis

Background

The aim was to assess serum magnesium levels in relation to prevalence of knee chondrocalcinosis in two population-based Chinese studies.

Methods

Data included in this analysis consisted of two population-based cross-sectional studies, i.e., the Xiangya Hospital Health Management Center Study and the Xiangya Osteoarthritis (XO) Study I. A bilateral knee anteroposterior radiograph was obtained from each subject. Radiographic knee chondrocalcinosis was present if there was definite linear cartilage calcification. Serum magnesium concentration was measured using the chemiluminescence method. We examined the relation of serum magnesium levels to prevalence of knee chondrocalcinosis using generalized estimating equations.

Results

The prevalence of knee chondrocalcinosis was 1.4% in the Xiangya Hospital Health Management Center Study (n = 12,631). Compared with the lowest tertile, the age, sex and body mass index (BMI)-adjusted odds ratios (ORs) of chondrocalcinosis were 0.59 (95% CI 0.40–0.87) and 0.49 (95% CI 0.33–0.72) in the second and the third tertiles of serum magnesium, respectively (P for trend <0.001). The prevalence of knee chondrocalcinosis in the XO Study I (n = 1316) was 4.1%. The age, sex and BMI-adjusted ORs of chondrocalcinosis were 0.67 (95% CI 0.34–1.30) in the second and 0.45 (95% CI 0.21–0.94) in the third tertile of serum magnesium when compared with the lowest tertile (P for trend = 0.030). Similar results were observed in men and women in both studies. Adjusting for additional potential confounders did not change the results materially.

Conclusions

Subjects with lower levels of serum magnesium, even within the normal range, had higher prevalence of knee chondrocalcinosis in a dose-response relationship manner, suggesting that magnesium may have a preventive or therapeutic potential for knee chondrocalcinosis.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-017-1450-6) contains supplementary material, which is available to authorized users.

Vitamin D deficiency is associated with metabolic syndrome in postmenopausal women

OBJECTIVE

To evaluate the association between vitamin D (VD) deficiency and risk factors for metabolic syndrome (MetS) in postmenopausal women.

STUDY DESIGN

Observational, cross-sectional cohort study.

MAIN OUTCOME MEASURES

In this study, 463 women, aged 45-75 years, with amenorrhea >12months, without VD supplementation or established cardiovascular disease were included. Clinical and anthropometric data were collected. Biochemical parameters, including total cholesterol (TC), HDL, LDL, triglycerides, glucose, insulin and 25-hydroxyvitamin-D [25(OH)D] were measured. Women meeting three or more of the following criteria were diagnosed with MetS: waist circumference >88cm, triglycerides ≥150mg/dL, HDL <50mg/dL, blood pressure ≥130/85mmHg and glucose ≥100mg/dL. Serum 25(OH)D levels were classified as sufficient (≥30ng/mL), insufficient (20-29ng/mL) or deficient (<20ng/mL). ANOVA, chi-square test and logistic regression (odds ratio, OR) were used for statistical analysis.

RESULTS

Serum 25(OH)D levels were sufficient in 148 women (32.0%), insufficient in 151 (32.6%) and deficient in 164 (35.4%). Women with low 25(OH)D levels had higher TC, triglycerides, insulin and HOMA-IR levels (p<0.05). MetS was detected in 57.8% (182/315) of women with hypovitaminosis D (insufficient and deficient) and in 39.8% (59/148) of those with sufficient VD​​ (p=0.003). In a multivariate logistic regression analysis, a low 25(OH)D level (<30ng/mL) was significantly associated with MetS (OR1.90, 95%CI=1.26-2.85), high triglyceride levels (OR1.55, 95%CI=1.13-2.35), and low HDL levels (OR1.60, 95%CI=1.19-2.40) (p<0.05) compared with women with sufficient 25(OH)D levels, after adjusting for age, time since menopause, body mass index, smoking and physical exercise. The mean concentration of 25(OH)D decreased with increasing numbers of MetS components (p=0.016).

CONCLUSIONS

VD deficiency in postmenopausal women was associated with a higher prevalence of MetS. Women with VD deficiency had a higher risk of MetS, hypertriglyceridemia and low HDL than those with adequate levels.

The association of vitamin D deficiency and glucose control among diabetic patients

Objective

To evaluate the association between the level of vitamin D and glycemic control among patients with diabetes.

Research design and method

We analyzed data collected from NHANES 2003–2006. We included only non-pregnant adult diabetic persons 18 years or older. Participants who had vitamin D level less than 20 ng/ml were considered as having vitamin D deficiency. Participants were considered to have a glucose control if the HbA_1c level was less than 7% [53 mmol/L]. We used student’s t test to compare the difference in HbA_1c means between people with Diabetes with and without a vitamin D deficiency. We used a multivariate logistic regression model to predict the relationship between glucose control and vitamin D deficiency. We used race/ethnicity, BMI, age, gender, type of diabetic medication used, having health insurance or not, and comorbid conditions (hypertension, anemia, cholesterol, liver disease, and kidney disease) as control variables.

Results

The study population included a total of 929 non-institutionalized, non-pregnant, diabetic adult persons. About 57% of patients with diabetes had a vitamin D deficiency. Blacks (non-Hispanic patients) with diabetes had the highest rate of vitamin D deficiency (79%). The unadjusted means of HbA_1c were significantly different between diabetic patients with no vitamin D deficiency and those with a vitamin D deficiency (7.06% [54 mmol/L], 7.56 % [59 mmol/L], respectively, P < 0.0001). Multivariate adjustment showed a small but not significant, increase in odds (11%) of having uncontrolled diabetes in patients with a vitamin D deficiency after adjustment for other factors.

Conclusion

Vitamin D deficiency is very common in patients with diabetes. We found no significant association between vitamin D level and glycemic control in patients with diabetes after adjustment for control variables.

Education achievement and type 2 diabetes-what mediates the relationship in older adults? Data from the ESTHER study: a population-based cohort study

OBJECTIVE

The study aims to identify the mediating factors of the relationship between education achievement and incident type 2 diabetes mellitus (T2DM) in older adults.

DESIGN

Population-based cohort study.

SETTING

Participants were recruited from the German federal state of Saarland.

PARTICIPANTS

Participants were excluded if they had prevalent T2DM or missing data on prevalent T2DM, missing or zero follow-up time for incident T2DM or were under 50 years of age. The total sample consisted of 7462 individuals aged 50-75 years (42.8% men, mean age 61.7 years) at baseline (2000-02). The median follow-up time was 8.0 years.

METHODS

Cox proportional hazards regression was initially used to determine the direct association between education achievement and incident T2DM. Using the Baron and Kenny approach, we then investigated the associations between education achievement and incident T2DM with the potential mediators. The contribution of each of the putative mediating variables was then calculated.

RESULTS

A clear socioeconomic gradient was observed with regard to T2DM incidence with the lowest educated individuals at a greater risk of developing the disease during the follow-up period: HR (95% CI) high education: 0.52 (0.34 to 0.80); medium education: 0.80 (0.66 to 0.96). Seven of the variables considered explained a proportion of the education-T2DM relationship (body mass index, alcohol consumption, hypertension, fasting triglycerides, high-density lipoprotein (HDL) cholesterol, physical activity and smoking status), where the contribution of the variables ranged from 1.0% to 17.7%. Overall, the mediators explained 31.7% of the relationship.

CONCLUSION

By identifying the possible mediating factors of the relationship between education achievement and incident T2DM in older adults, the results of this study can be used to assist with the development of public health strategies that aim to reduce socioeconomic inequalities in T2DM.

Low vitamin D levels increase the risk of type 2 diabetes in older adults: A systematic review and meta-analysis

Low serum levels of 25 hydroxyvitamin D (25OHD) (hypovitaminosis D) is common in older adults and associated with several negative outcomes. The association between hypovitaminosis D and diabetes in older adults is equivocal, however. We conducted a meta-analysis investigating if hypovitaminosis D is associated with diabetes in prospective studies among older participants. Two investigators systematically searched major electronic databases, from inception until 10/07/2016. The cumulative incidence of diabetes among groups was estimated according to baseline serum 25OHD levels. Random effect models were used to assess the association between hypovitaminosis D and diabetes at follow-up. From 4268 non-duplicate hits, 9 studies were included; these followed 28,258 participants with a mean age of 67.7 years for a median of 7.7 years. Compared with higher levels of 25OHD, lower levels of 25OHD were associated with a higher risk of developing diabetes (6 studies; n=13,563; RR=1.31; 95% CI: 1.11-1.54; I²=37%). The findings remained significant after adjusting for a median of 11 potential confounders in all the studies available (9 studies; n=28,258; RR=1.17; 95% CI: 1.03-1.33; p=0.02; I²=0%). In conclusion, our data suggest that hypovitaminosis D is associated with an elevated risk of future diabetes in older people. Future longitudinal studies are required and should seek to confirm these findings and explore potential pathophysiological underpinnings.

Dysfunctional immunometabolic effects of vitamin D deficiency, increased cardiometabolic risk. Potential epidemiological alert in America?

Vitamin D deficiency is a serious public health problem worldwide that affects not only skeletal health, but also a wide range of acute and chronic diseases. However, there is still skepticism because of the lack of randomized, controlled trials to support association studies on the benefits of vitamin D for non-skeletal health. This review was based on articles published during the 1980-2015 obtained from the Cochrane Central Register of controlled trials, MEDLINE and PubMed, and focuses on recent challenges with regard to the definition of vitamin D deficiency and how to achieve optimal serum 25-hydroxyvitamin D levels from dietary sources, supplements, and sun exposure. The effect of vitamin D on epigenetic fetal programming and regulation of genes that may potentially explain why vitamin D could have such lifelong comprehensive health benefits is reviewed. Optimization of vitamin D levels in children and adults around the world has potential benefits to improve skeletal health and to reduce the risk of chronic diseases, including some types of cancer, autoimmune diseases, infectious diseases, type 2 diabetes mellitus, and severe cardiovascular disorders such as atherothrombosis, neurocognitive disorders, and mortality.

25-Hydroxyvitamin D Status and Risk for Colorectal Cancer and Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis of Epidemiological Studies

Epidemiological evidence suggests an association between low vitamin D status and risk for various outcomes including cardiovascular diseases, cancer, and type 2 diabetes mellitus (T2DM). Analyzing serum 25-hydroxyvitamin D [25(OH)D] is the most established means to evaluate an individual's vitamin D status. However, cutoff values for 25(OH)D insufficiency as well as for optimal 25(OH)D levels are controversial. This systematic review critically summarizes the epidemiological evidence regarding 25(OH)D levels and the risk for colorectal cancer and T2DM. The meta-analytical calculation revealed a pooled relative risk (RR) of 0.62 (CI 0.56-0.70; I² = 14.7%) for colorectal cancer and an RR of 0.66 (CI 0.61-0.73; I² = 38.6%) for T2DM when comparing individuals with the highest category of 25(OH)D with those in the lowest. A dose-response analysis showed an inverse association between 25(OH)D levels and RR for both outcomes up to concentrations of about 55 ng/mL for colorectal cancer and about 65 ng/mL for T2DM. At still higher 25(OH)D levels the RR increases slightly, consistent with a U-shaped association. In conclusion, a higher 25(OH)D status is associated with a lower risk for colorectal cancer and T2DM; however, this advantage is gradually lost as levels increase beyond 50-60 ng/mL.

SERUM 25-HYDROXYVITAMIN D(3) LEVELS IN TYPE 2 DIABETIC PATIENTS WITH NORMO-, MICRO-, AND MACROALBUMINURIA

Background

The aim of this study was to observe the differences in serum 25-hydroxyvitamin D(3) levels in nondiabetic healthy control subject and type 2 diabetic patients, and to investigate the differences in serum 25-hydroxyvitamin D(3) levels in type 2 diabetic patients with normo-, micro- and macroalbuminuria.

Patients and Methods

Total 140 nondiabetic healthy controls and 384 type 2 diabetic patients (156 normoalbuminuric, 152 microalbuminuric and 76 macroalbuminuric) were included in the study. 25-hydroxyvitamin D(3) levels were measured in sera with the method of electrochemiluminescence using modular immunoassay analyzer.

Results

Vitamin D deficiency was detected in 70.85% and 22.9% of type 2 diabetic patients and nondiabetic healthy controls, respectively. Serum 25-hydroxyvitamin D(3) levels were significantly lower in type 2 diabetic patients compared to nondiabetic healthy controls (16.4 ± 9.5 ng/mL vs. 28.2 ± 11.6 ng/mL, p=0.0001). Serum 25-hydroxyvitamin D(3) levels were lower in albuminuric and nonalbuminuric diabetic patients (14.3 ± 7.9 ng/mL vs. 19.6±10.9 ng/mL, respectively, p=0.013). Serum 25-hydroxyvitamin D(3) levels were 19.6 ± 10.9 ng/mL in normoalbuminuric, 14.9 ± 8.8 ng/mL in microalbuminuric and 12.9 ± 5.8 ng/mL in macroalbuminuric diabetic patients. While lower serum 25-hydroxyvitamin D(3) levels were detected both in microalbuminuric (p=0.028) and macroalbuminuric diabetic patients (p=0.014) compared to normoalbuminuric diabetic patients, 25-hydroxyvitamin D(3) levels did not change significantly between microalbuminuric and macroalbuminuric diabetic patients (p=0.67). Serum 25-hydroxyvitamin D(3) levels correlated negatively with urinary albumin excretion (r=-0.24, p=0.016) in patients with diabetes mellitus.

Conclusion

Findings of the present study demonstrated reduced serum 25-hydroxyvitamin D(3) levels which were significantly related with albuminuria in type 2 diabetic patients.

Vitamin D deficiency in patients admitted to the general ward with breast, lung, and colorectal cancer in Buenos Aires, Argentina

A high prevalence of hypovitaminosis D has been reported in cancer patients. Low levels of 25-(OH)-vitamin D were found in 158 of 162 (97.5%) inpatients with breast, lung, and colorectal cancer under active treatment, with severe deficiency (<20 ng/ml) in 77.2% and mild deficiency (20-30 ng/ml) in 20.4%.

PURPOSE

A high prevalence of vitamin D deficiency has been reported in cancer patients. Nevertheless, vitamin D serum levels have been checked in few patients. Information about the frequency of hypovitaminosis D in cancer patients in Argentina is unknown. The aim of the study was to assess the frequency of vitamin D deficiency in patients with breast, lung, and colorectal cancer.

METHODS

A prospective observational study was designed for cancer patients admitted to the general ward in 2014. The patients included had breast, lung, and colorectal cancer. All of them were under active treatment. The serum level of 25-(OH)-vitamin D [25-(OH)-D] was measured and categorized as sufficiency (>30 ng/ml), mild deficiency (20-30 ng/ml), and severe deficiency (<20 ng/ml).

RESULTS

A total of 162 patients were included, 98.2% were in stages III-IV. Median level of 25-(OH)-D was 15.3 ng/ml (range 4.1-103.6 ng/ml). Serum levels <30 ng/ml were found in 158 (97.5%) patients, severe deficiency in 125 cases (77.2%) and mild deficiency in 33 cases (20.4%). In patients under chemo/hormone therapy, the median level was 15.3 ng/ml (range 4.1-103.6 ng/ml) and in those under concurrent therapy was 17.1 ng/ml (range 7.4-58.5 ng/ml); p = 0.1944. There were no statistical differences in severe or mild deficiency of vitamin D among breast, lung, and colorectal cancer patients.

CONCLUSION

The study found a high prevalence of vitamin D deficiency in hospitalized cancer patients under active treatment. Many authors have recommended dosing vitamin D levels in this population; normalizing serum levels is difficult.

The Effect of Vitamin D Supplementation on Glycemic Control and Lipid Profile in Patients with Type 2 Diabetes Mellitus

AIM

The aim of this study was to evaluate the effect of vitamin D supplementation in patients with type 2 diabetes mellitus (T2DM) with regard to their glycemic control and lipid profile.

METHODS

One hundred subjects with T2DM were recruited and given 4500 IU/day of vitamin D for 2 months. 25-Hydroxyvitamin D [25(OH)D], fasting blood glucose (FBG), glycosylated hemoglobin A1c (HbA1c), and lipid profile were measured pre- and postsupplementation.

RESULTS

There was a significant increase in the mean value of 25(OH)D level after supplementation (baseline level 16 ± 5.3 ng/ml vs. after supplement level 49.2 ± 17.7 ng/ml, p < 0.05). Both FBG and HbA1c but not lipid profile were significantly decreased after supplementation. However, the univariate general linear model between 25(OH)D percentiles and lipid profile levels showed that diabetic subjects with high 25(OH)D levels (>61 ng/ml) had significantly lower levels of total cholesterol and low-density lipoprotein cholesterol (LDL-C) in comparison to those in the low or middle percentiles. Furthermore, participants in a higher percentile had a significantly higher level of high-density lipoprotein cholesterol (HDL-C) than those in the middle percentile. Lipid profile levels were not affected by the supplement except for triglycerides (TG) levels in females, which were significantly decreased.

CONCLUSIONS

Vitamin D supplementation may be beneficial to diabetic subjects because it improved glycemic control. Diabetic subjects with high 25(OH)D levels (>61 ng/ml) had better lipid profiles.

The Rotterdam Study: 2016 objectives and design update

The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in The Netherlands. The study targets cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric, dermatological, otolaryngological, locomotor, and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in over 1200 research articles and reports (see www.erasmus-epidemiology.nl/rotterdamstudy ). This article gives the rationale of the study and its design. It also presents a summary of the major findings and an update of the objectives and methods.

Serum Vitamin D Concentrations Are Not Associated with Insulin Resistance in Swiss Adults

BACKGROUND

Low vitamin D status has been associated with an increased risk of developing type 2 diabetes and insulin resistance (IR), although this has been recently questioned.

OBJECTIVE

We examined the association between serum vitamin D metabolites and incident IR.

METHODS

This was a prospective, population-based study derived from the CoLaus (Cohorte Lausannoise) study including 3856 participants (aged 51.2 ± 10.4 y; 2217 women) free from diabetes or IR at baseline. IR was defined as a homeostasis model assessment (HOMA) index >2.6. Fasting plasma insulin and glucose were measured at baseline and at follow-up to calculate the HOMA index. The association of vitamin D metabolites with incident IR was analyzed by logistic regression, and the results were expressed for each independent variable as ORs and 95% CIs.

RESULTS

During the 5.5-y follow-up, 649 (16.9%) incident cases of IR were identified. Participants who developed IR had lower baseline serum concentrations of 25-hydroxyvitamin D3 [25(OH)D3 (25-hydroxycholecalciferol); 45.9 ± 22.8 vs. 49.9 ± 22.6 nmol/L; P < 0.001], total 25(OH)D3 (25(OH)D3 + epi-25-hydroxyvitamin D3 [3-epi-25(OH)D3]; 49.1 ± 24.3 vs. 53.3 ± 24.1 nmol/L; P < 0.001), and 3-epi-25(OH)D3 (4.2 ± 2.9 vs. 4.3 ± 2.5 nmol/L; P = 0.01) but a higher 3-epi- to total 25(OH)D3 ratio (0.09 ± 0.05 vs. 0.08 ± 0.04; P = 0.007). Multivariable analysis adjusting for month of sampling, age, and sex showed an inverse association between 25(OH)D3 and the likelihood of developing IR [ORs (95% CIs): 0.86 (0.68, 1.09), 0.60 (0.46, 0.78), and 0.57 (0.43, 0.75) for the second, third, and fourth quartiles compared with the first 25(OH)D3 quartile; P-trend < 0.001]. Similar associations were found between total 25(OH)D3 and incident IR. There was no significant association between 3-epi-25(OH)D3 and IR, yet a positive association was observed between the 3-epi- to total 25(OH)D3 ratio and incident IR. Further adjustment for body mass index, sedentary status, and smoking attenuated the association between 25(OH)D3, total 25(OH)D3, and the 3-epi- to total 25(OH)D3 ratio and the likelihood of developing IR.

CONCLUSION

In the CoLaus study in healthy adults, the risk of incident IR is not associated with serum concentrations of 25(OH)D3 and total 25(OH)D3.

Screening for vitamin D deficiency: a systematic review for the U.S. Preventive Services Task Force

BACKGROUND

Vitamin D deficiency has been associated with adverse health outcomes.

PURPOSE

To systematically review benefits and harms of vitamin D screening in asymptomatic adults.

DATA SOURCES

Ovid MEDLINE (through the third week of August 2014), Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews.

STUDY SELECTION

Randomized trials of screening for and treatment of vitamin D deficiency and case-control studies nested within the Women's Health Initiative.

DATA EXTRACTION

One investigator abstracted data, a second reviewed data for accuracy, and 2 investigators independently assessed study quality using predefined criteria.

DATA SYNTHESIS

No study examined the effects of vitamin D screening versus no screening on clinical outcomes. Vitamin D treatment was associated with decreased mortality versus placebo or no treatment (11 studies; risk ratio [RR], 0.83 [95% CI, 0.70 to 0.99]), although benefits were no longer seen after trials of institutionalized persons were excluded (8 studies; RR, 0.93 [CI, 0.73 to 1.18]). Vitamin D treatment was associated with possible decreased risk for having at least 1 fall (5 studies; RR, 0.84 [CI, 0.69 to 1.02]) and falls per person (5 studies; incidence rate ratio, 0.66 [CI, 0.50 to 0.88]) but not fractures (5 studies; RR, 0.98 [CI, 0.82 to 1.16]). Vitamin D treatment was not associated with a statistically significant increased risk for serious adverse events (RR, 1.17 [CI, 0.74 to 1.84]).

LIMITATION

Variability across studies in 25-hydroxyvitamin D assays and baseline levels, treatment doses, use of calcium, and duration of follow-up.

CONCLUSION

Treatment of vitamin D deficiency in asymptomatic persons might reduce mortality risk in institutionalized elderly persons and risk for falls but not fractures.

PRIMARY FUNDING SOURCE

Agency for Healthcare Research and Quality.

Association of vitamin D levels with type 2 diabetes in older working adults

OBJECTIVES

Increasing evidence suggests that vitamin D plays a role in the development of chronic diseases including type 2 diabetes (DM). Aim of the study was to explore the association of vitamin D levels with prevalent DM in a sample of predominantly healthy working adults older than 45 years.

METHODS

This cross-sectional study (2009-2011) involved 1821 employees of a German engineering company (83.1% male, mean age 51.9 ±5.6 years). Sociodemographics and medical history were assessed by self-report. Clinical characteristics were obtained including blood samples to determine vitamin D levels and diabetes status by fasting plasma glucose (FPG) and glycosylated hemoglobin (HbA1c). Vitamin D was grouped into one of four categories (<10 ng/ml, 10-19.9 ng/ml, 20-29.9 ng/ml, ≥30 ng/ml). Bivariate associations between vitamin D categories and a composite indicator for DM (FPG ≥126 mg/dl or HbA1c ≥6.5% or self-reported diagnosis) were calculated; multivariable models tested this association further, controlling for potential confounders.

RESULTS

Severe vitamin D deficiency (<10 ng/ml) was associated with increasing FPG (β 3.13; 95% CI: 0.78, 5.47; p≤0.01) and HbA1c (β 0.15; 95% CI: 0.08, 0.23; p≤0.001) values in adjusted linear regression models. In multivariable models, severe vitamin D deficiency was associated with DM (OR 2.55; 95%CI 1.16, 5.62; p≤0.05) after controlling for potential confounders.

CONCLUSIONS

Vitamin D deficiency is associated with prevalent DM in working older adults. The findings highlight that the workplace may be a unique location for conducting large-scale health screening to identify those at risk of DM using vitamin D.

A prospective observational study of all-cause mortality in relation to serum 25-OH vitamin D3 and parathyroid hormone levels in patients with type 2 diabetes

BACKGROUND

Low levels of vitamin D have been related to increased mortality and morbidity in several non-diabetic studies. We aimed to prospectively study relationships between serum 25-OH vitamin D3 (vitamin D) and of serum parathyroid hormone (PTH) to total mortality in type 2 diabetes. We also aimed to compare the levels of these potential risk-factors in patients with and without diabetes.

METHODS

The main study design was prospective and observational. We used baseline data from 472 men and 245 women who participated in the "Cardiovascular Risk factors in Patients with Diabetes-a Prospective study in Primary care" study. Patients were 55-66 years old at recruitment, and an age-matched non-diabetic sample of 129 individuals constituted controls for the baseline data. Carotid-femoral pulse-wave velocity (PWV) was measured with applanation-tonometry and carotid intima-media thickness (IMT) with ultrasound. Patients with diabetes were followed for all-cause mortality using the national Swedish Cause of Death Registry.

RESULTS

Levels of vitamin D were lower in patients with diabetes than in controls, also after correction for age and obesity, while PTH levels did not differ. Nine women and 24 men died during 6 years of median follow up of the final cohort (n = 698). Vitamin D levels were negatively related to all-cause mortality in men independently of age, PTH, HbA1c, waist circumference, 24-h systolic ambulatory-blood pressure (ABP) and serum-apoB (p = 0.049). This finding was also statistically significant when PWV and IMT were added to the analyses (p = 0.028) and was not affected statistically when medications were also included in the regression-analysis (p = 0.01). In the women with type 2 diabetes, levels of PTH were positively related with all-cause mortality in the corresponding calculations (p = 0.016 without PWV and IMT, p = 0.006 with PWV and IMT, p = 0.045 when also adding medications to the analysis), while levels of vitamin D was without statistical significance (p >0.9).

CONCLUSIONS

Serum vitamin D in men and serum PTH in women give prognostic information in terms of total-mortality that are independent of regular risk factors in addition to levels of ABP, IMT and PWV.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01049737.

Early origins of chronic obstructive lung diseases across the life course

Chronic obstructive lung diseases, like asthma and chronic obstructive pulmonary disease, have high prevalences and are a major public health concern. Chronic obstructive lung diseases have at least part of their origins in early life. Exposure to an adverse environment during critical periods in early life might lead to permanent developmental adaptations which results in impaired lung growth with smaller airways and lower lung volume, altered immunological responses and related inflammation, and subsequently to increased risks of chronic obstructive lung diseases throughout the life course. Various pathways leading from early life factors to respiratory health outcomes in later life have been studied, including fetal and early infant growth patterns, preterm birth, maternal obesity, diet and smoking, children's diet, allergen exposure and respiratory tract infections, and genetic susceptibility. Data on potential adverse factors in the embryonic and preconception period and respiratory health outcomes are scarce. Also, the underlying mechanisms how specific adverse exposures in the fetal and early postnatal period lead to chronic obstructive lung diseases in later life are not yet fully understood. Current studies suggest that interactions between early environmental exposures and genetic factors such as changes in DNA-methylation and RNA expression patterns may explain the early development of chronic obstructive lung diseases. New well-designed epidemiological studies are needed to identify specific critical periods and to elucidate the mechanisms underlying the development of chronic obstructive lung disease throughout the life course.

The Generation R Study: Biobank update 2015

The Generation R Study is a population-based prospective cohort study from fetal life until adulthood. The study is designed to identify early environmental and genetic causes and causal pathways leading to normal and abnormal growth, development and health from fetal life, childhood and young adulthood. In total, 9,778 mothers were enrolled in the study. Data collection in children and their parents include questionnaires, interviews, detailed physical and ultrasound examinations, behavioural observations, Magnetic Resonance Imaging and biological samples. Efforts have been conducted for collecting biological samples including blood, hair, faeces, nasal swabs, saliva and urine samples and generating genomics data on DNA, RNA and microbiome. In this paper, we give an update of the collection, processing and storage of these biological samples and available measures. Together with detailed phenotype measurements, these biological samples provide a unique resource for epidemiological studies focused on environmental exposures, genetic and genomic determinants and their interactions in relation to growth, health and development from fetal life onwards.

Vitamin D levels and cognition in elderly adults in China

OBJECTIVES

To evaluate the association between vitamin D level and cognitive impairment in individuals aged 60 and older.

DESIGN

Cross-sectional cohort study.

SETTING

Chinese Longitudinal Healthy Longevity Survey, a community-based cohort study in areas in China where the density of centenarians is exceptionally high.

PARTICIPANTS

Individuals with mean age of 84.9 ± 12.7 (N = 2,004).

MEASUREMENTS

Participants' cognitive state was evaluated using the Mini-Mental State Examination (MMSE). Vitamin D was measured in plasma using an enzyme-linked immunoassay.

RESULTS

The cross-sectional association between quartiles of plasma vitamin D level and cognitive impairment (MMSE score <18) was modeled using logistic regressions. Plasma vitamin D levels were lower in individuals with cognitive impairment (31.9 ± 15.3 nmol/L) than in those without (45.6 ± 19.6 nmol/L). There was a reverse association between plasma vitamin D and cognitive impairment. After adjusting for age, sex, chronic conditions, smoking and drinking habits, outdoor activities, depression, and activity of daily living limitations, the association remained significant. The multivariable-adjusted odds ratio for lowest versus highest vitamin D levels was 2.15 (95% confidence interval (CI) = 1.05-4.41) for cognitive impairment, and the multivariable odds ratio associated with a 1-standard deviation decrement in plasma vitamin D was 1.32 (95% CI = 1.00-1.74) for cognitive impairment.

CONCLUSION

Low plasma vitamin D levels were associated with greater odds of cognitive impairment. Further prospective studies in Asian populations are needed to examine the causal direction of this association.

Vitamin D: a critical and essential micronutrient for human health

Vitamin D is a micronutrient that is needed for optimal health throughout the whole life. Vitamin D₃ (cholecalciferol) can be either synthesized in the human skin upon exposure to the UV light of the sun, or it is obtained from the diet. If the photoconversion in the skin due to reduced sun exposure (e.g., in wintertime) is insufficient, intake of adequate vitamin D from the diet is essential to health. Severe vitamin D deficiency can lead to a multitude of avoidable illnesses; among them are well-known bone diseases like osteoporosis, a number of autoimmune diseases, many different cancers, and some cardiovascular diseases like hypertension are being discussed. Vitamin D is found naturally in only very few foods. Foods containing vitamin D include some fatty fish, fish liver oils, and eggs from hens that have been fed vitamin D and some fortified foods in countries with respective regulations. Based on geographic location or food availability adequate vitamin D intake might not be sufficient on a global scale. The International Osteoporosis Foundation (IOF) has collected the 25-hydroxy-vitamin D plasma levels in populations of different countries using published data and developed a global vitamin D map. This map illustrates the parts of the world, where vitamin D did not reach adequate 25-hydroxyvitamin D plasma levels: 6.7% of the papers report 25-hydroxyvitamin D plasma levels below 25 nmol/L, which indicates vitamin D deficiency, 37.3% are below 50 nmol/Land only 11.9% found 25-hydroxyvitamin D plasma levels above 75 nmol/L target as suggested by vitamin D experts. The vitamin D map is adding further evidence to the vitamin D insufficiency pandemic debate, which is also an issue in the developed world. Besides malnutrition, a condition where the diet does not match to provide the adequate levels of nutrients including micronutrients for growth and maintenance, we obviously have a situation where enough nutrients were consumed, but lacked to reach sufficient vitamin D micronutrient levels. The latter situation is known as hidden hunger. The inadequate vitamin D status impacts on health care costs, which in turn could result in significant savings, if corrected. Since little is known about the effects on the molecular level that accompany the pandemic like epigenetic imprinting, the insufficiency-triggered gene regulations or the genetic background influence on the body to maintain metabolic resilience, future research will be needed. The nutrition community is highly interested in the molecular mechanism that underlies the vitamin D insufficiency caused effect. In recent years, novel large scale technologies have become available that allow the simultaneous acquisition of transcriptome, epigenome, proteome, or metabolome data in cells of organs. These important methods are now used for nutritional approaches summarized in emerging scientific fields of nutrigenomics, nutrigenetics, or nutriepigenetics. It is believed that with the help of these novel concepts further understanding can be generated to develop future sustainable nutrition solutions to safeguard nutrition security.

Serum 25-hydroxyvitamin D and incidence of diabetes in elderly people: the PRO.V.A. study

CONTEXT

Increasing research has shown that low levels of serum 25-hydroxyvitamin (25OHD) predict the onset of diabetes, but no research is available on this issue in elderly people.

OBJECTIVE

Our objective was to examine whether low serum levels of 25OHD are associated with a higher risk of incident type 2 diabetes over a lengthy follow-up in a representative group of elderly people.

DESIGN AND SETTING

This was a population-based cohort study as part of the Progetto Veneto Anziani (Pro.V.A.) Study over a follow-up of 4.4 years in the general community.

PARTICIPANTS

PARTICIPANTS included 2227 participants (1728 with follow-up visits and 499 died during the follow-up) over 65 years of age without diabetes at baseline, of 2352 initially included.

MAIN OUTCOME MEASURE

The main outcome measure was incident diabetes.

RESULTS

There were no baseline differences in known factors for the onset of diabetes (body mass index, waist circumference, total cholesterol, renal function, and hemoglobin A1c levels) between the groups with different serum 25OHD levels (≤ 25, 25-50, 50-75, and ≥ 75 nmol/L). Over a 4.4-year follow-up, 291 individuals developed diabetes, with an incidence of 28 events per 1000 person-years. No significant difference in the incidence of diabetes emerged between the baseline 25OHD groups. Cox's regression analysis, adjusted for potential confounders, revealed no relationship between low vitamin D levels and incident diabetes during the follow-up (hazard ratio [HR] = 1.05, 95% confidence interval [CI] = 0.76-1.45, P = .77; HR = 1.44, 95% CI = 0.95-1.98, P = .12; and HR = 1.37, 95% CI = 0.87-2.16, P = .17 for those with 25OHD ≤25, 25-50, and 50-75 nmol/L, respectively).

CONCLUSION

Baseline serum concentrations of 25OHD were not associated with the incidence of diabetes in community-dwelling elderly people over a follow-up of 4.4 years.

Prevalence of vitamin d deficiency among Indian menopausal women and its correlation with diabetes: A first Indian cross sectional data

AIM AND OBJECTIVE

To evaluate prevalence of Vitamin D deficiency and establish any correlation between diabetes and vitamin D deficiency among postmenopausal women.

MATERIALS AND METHODS

The 25-hydroxy vitamin D [25 (OH) D] concentrations were measured by competitive in-vitro quantitative immunoassay. The subjects were classified as vitamin D-deficient, insufficient or sufficient on the basis of 25 (OH) D concentrations of < 20 ng/mL, 20-30 ng/mL or > 30 ng/mL respectively. The apparently normal postmenopausal women (PMW) were subjected to fasting blood sugar levels to analyse any correlation between vitamin D deficiency and diabetes.

RESULTS

Vitamin D deficiency was observed in 53.35% of the population, 19.48% had insufficiency and 26.83% had adequate Vitamin D levels. In 12.14% of the study population fasting blood glucose was > 110 mg/dl and rest of the subjects were between the normal range which is 70-110mg/dl. Correlation between raised blood sugar levels and Vitamin D deficiency among PMW was non-significant (P = 0.324).

CONCLUSION

High prevalence of vitamin D deficiency exists among apparently healthy Indian PMW. However, the current study failed to show any statistical correlation between vitamin D deficiency and existence of diabetes, which may be due to small sample size.

The relationship between vitamin D and obesity

Currently, vitamin D deficiency and obesity are pandemic diseases and they are associated with cardiovascular (CV) disease, metabolic syndrome and type 2 diabetes mellitus (T2DM) and other diseases. Concentrations of 25-hydroxyvitamin D (25(OH)D) (25D) are considered as the best indicator of total body vitamin D stores. An association between reduced circulating 25D concentrations and obesity is well known, but the mechanisms are not totally clear. The role of vitamin D supplementation is still uncertain and prospective interventions will establish its influence, if any, in the treatment of obesity. Vitamin D deficiency is associated with the presence of a cardiometabolic risk profile in the obese. Future trials may establish a role for Vitamin D supplementation in individuals at increased CV risk.

Is vitamin D deficiency a cause of increased morbidity and mortality at older age or simply an indicator of poor health?

To assess whether vitamin D deficiency is a cause of increased morbidity and mortality or simply an indicator of poor health, we assessed (1) the cross-sectional and longitudinal association of vitamin D deficiency with self-rated health (SRH) and frailty and (2) the association of vitamin D deficiency with mortality, with and without control for SRH and frailty. Analyses were performed in 9,579 participants of the German, population-based ESTHER cohort (age-range at baseline: 50-74 years), with follow-ups after 2, 5 and 8 years (mortality: 12 years). During follow-up, 129 subjects newly reported poor SRH, 510 developed frailty and 1,450 died. In cross-sectional analyses, subjects with vitamin D deficiency had higher odds of a poor SRH and frailty but no association with SRH or frailty was observed in longitudinal analyses. The association of vitamin D deficiency with all-cause and several cause-specific mortalities was strong and unaltered by time-dependent adjustment for classic mortality risk factors, SRH and frailty. In conclusion, vitamin D deficiency may not cause frailty or poor general health but may nevertheless be a prognostic marker for mortality, independent of the individual's morbidity.

Obesity and vitamin D deficiency: trends to promote a more proatherogenic cardiometabolic risk profile

Vitamin D deficiency is associated with cardiometabolic risk factors (eg, hypertension, insulin resistance, type 2 diabetes mellitus, obesity, and dyslipidemia). We studied 50 obese patients (body mass index [BMI]: 43.5 ± 9.2 kg/m(2)) and 36 normal weight participants (BMI: 22.6 ± 1.9 kg/m(2)). The prevalence of vitamin D deficiency (25-hydroxyvitamin D, 25(OH)D < 50 nmol/L) was 88% among obese patients and 31% among nonobese individuals; 25(OH)D levels were lower in the obese group (27.3 ± 13.7 vs 64.6 ± 21.3 nmol/L; P < .001). There was a negative correlation between vitamin D level and anthropometric indicators of obesity: BMI (r = -0.64; P < .001), waist circumference (r = -0.59; P < .001), and body fat percentage (r = -0.64; P < .001) as well as with fasting plasma insulin (r = -0.35; P < .001) and homeostasis model assessment of insulin resistance (r = -0.35; P < .001). In conclusion, we observed a higher prevalence of vitamin D deficiency among obese participants and this was associated with a proatherogenic cardiometabolic risk profile.