Vitamin D and all-cause mortality among adults in USA: findings from the National Health and Nutrition Examination Survey Linked Mortality Study

Associations of vitamin D status with all-cause and cause-specific mortality in long-term prescription opioid users

Objective

This study aimed to investigate the association between serum 25-hydroxyvitamin D (25(OH)D) concentrations and mortality in long-term prescription opioid users.

Methods

The study included 1856 long-term prescription opioid users from the National Health and Nutrition Examination Survey (NHANES, 2001-2018). Mortality status were determined by matching with the National Death Index (NDI) records until December 31, 2019. Multivariable Cox proportional hazard models were constructed to assess the association.

Results

Over a median follow-up period of 7.75 years, there were 443 cases of all-cause mortality, including 135 cardiovascular disease (CVD) deaths and 94 cancer deaths. After multivariable adjustment, participants with serum 25(OH)D concentrations within 50.00 to <75.00 nmol/L and ≥ 75 nmol/L had a lower risk of all-cause mortality, with hazard ratios (HRs) of 0.50 (95% confidence interval [CI] 0.29, 0.86) and 0.54 (95% CI 0.32, 0.90), respectively. Nevertheless, no significant association was found between serum 25(OH)D concentrations and the risk of CVD or cancer mortality. The RCS analysis revealed a non-linear association of serum 25(OH)D concentration with all-cause mortality (p for non-linear = 0.01). Per 1-unit increment in those with serum 25(OH)D concentrations <62.17 nmol/L corresponded to a 2% reduction in the risk of all-cause mortality (95% CI 0.97, 1.00), but not changed significantly when 25(OH)D concentrations ≥62.17 nmol/L.

Conclusion

In conclusion, a non-linear association existed between serum 25(OH)D concentrations and all-cause mortality in long-term prescription opioid users. Maintaining serum 25(OH)D concentrations ≥62.17 nmol/L may be beneficial in preventing all-cause mortality in this population.

Association of serum 25-hydroxyvitamin D concentrations with all-cause and cardiovascular mortality among US adults with prehypertension: a prospective cohort study

BACKGROUND

Prehypertension affects 25-50% of adults worldwide and no prior study has examined the relationship between serum 25-hydroxyvitamin D [25(OH)D] concentrations and mortality risk in individuals with prehypertension. This study aims to investigate the association of serum 25(OH)D concentrations with all-cause and CVD mortality among prehypertensive adults by utilizing data from the US National Health and Nutrition Examination Survey (NHANES) 2007-2014 and linked 2019 mortality file.

METHODS

We included 4345 prehypertensive adults who participated in the NHANES between 2007 and 2014 and were followed up until 31 December 2019. Weighted Cox proportional hazards models were used with adjustments for multiple covariates to calculate the hazard ratio (HR) and 95% confidence interval (CI) for the risks of dying from any cause and CVD.

RESULTS

During a median follow-up of 8.8 years, 335 deaths from any causes were documented, of which 88 participants died from CVD. Compared with participants with sufficient 25(OH)D (≥ 75 nmol/L), the multivariate-adjusted HRs and 95% CIs for participants with severe deficiency (< 25 nmol/L), moderate deficiency (25-49.9 nmol/L), and insufficient concentrations (50-74.9 nmol/L) of serum 25(OH)D for all-cause death were 2.83 (1.46-5.52), 1.17 (0.74-1.86), and 1.36 (0.93-1.98), respectively. Similarly, the multivariable-adjusted HRs and 95%CIs for CVD death were 4.14 (1.10-15.51), 1.23 (0.46-3.28), and 1.73 (0.96-3.14), respectively. We found that there was a 9% reduction in the risk of death from all causes and a 14% reduction in the risk of death from CVD for every 10 nmol/L increase in serum 25(OH)D concentrations.

CONCLUSION

Severe serum 25(OH)D deficiency among prehypertensive adults was associated with increased risk of mortality from all causes as well as from CVD. Our work suggests that supplementing with vitamin D may prevent premature death in severely deficient individuals with prehypertension.

Multiple vitamin co-exposure and mortality risk: A prospective study

BACKGROUND & AIMS

Existing epidemiological studies explored the associations of circulating vitamins and mortality focusing on individual vitamin effects, and controversial findings were obtained. The joint effects of multiple vitamin co-exposure are worth studying. The study aimed to elucidate the associations of circulating vitamins and the joint effects of these vitamins' co-exposure with all-cause and cause-specific mortality risks.

METHODS

We prospectively evaluated the associations of the concentrations of six kinds of vitamins (A, D, E, C, B12 and B9) in serum with risks for all-cause and cause-specific mortalities among U.S. adults. Mortality status and cause of death were determined by NHANES-linked public available files dated up to 31 December 2015. An unsupervised K-means clustering method was used to cluster the participants into several vitamin co-exposure patterns. The Cox proportional hazards model was used for statistical analysis.

RESULTS

A total of 1404 deaths occurred during a median of 10.9 years follow-up among 8295 participants. In multivariable adjustment, increasing levels of vitamin D were associated with reduced all-cause and cause-specific mortality risks. A J-shaped nonlinear exposure-response relationship was observed between all studied vitamins (except for vitamin D) and all-cause mortality risk. Four co-exposure patterns were generated based on the studied vitamins, as follows: low-level exposure (cluster 1), vitamin A/D exposure (cluster 2), water-soluble vitamin exposure (cluster 3) and high-level exposure (cluster 4). Compared with those in cluster 1, participants in cluster 2 had lower all-cause and cancer mortality risks, with hazard ratios (95% confidence intervals [CIs]) of 0.67 (0.53, 0.85) and 0.45 (0.29, 0.71), respectively.

CONCLUSIONS

The findings in this study indicated that high circulating vitamin D levels were associated with reduced mortality risk among U.S. adults. Vitamin co-exposure at moderate levels appropriately contributed to low all-cause and cancer mortality risks. Our findings provided a novel perspective for exploring the joint health effects of multivitamin co-exposure. Future investigations are needed to further unravel the underlying mechanisms of possible vitamin interactions.

Investigation of vitamin D levels in patients with Sudden Sensory-Neural Hearing Loss and its effect on treatment

BACKGROUND

Due to high prevalence of vitamin D deficiency and the possible association with Sudden Sensory-Neural Hearing Loss (SSNHL) finding the main causes and appropriate treatments are highly essential. This study aimed to investigate vitamin D levels in patients suffering SSNHL and its effect on response to treatment.

MATERIALS AND METHODS

This cross-sectional study was performed on two groups of case (34 SSNHL patients) and control (34 healthy subjects without risk of hearing loss). All patient information such as age, sex, audiogram illustration of hearing frequency and the level of vitamin D were recorded at baseline. Patients with SSNHL received routine treatments such as 10 days of 1 mg/kg/day steroid and the response or lack of complete response to treatment was recorded and analyzed according to the audiometry.

RESULTS

Vitamin D level in SSNHL group with a mean of 19.28 ± 9.56 ng/ml was significantly less than the control group (25.71 ± 11.21 ng/ml; P value < 0.001). After treatment, 76.5% were completely recovered and 23.5% did not recover completely. Factors such as age, sex and level of initial hearing loss did not have a significant effect on the response to treatment, but the level of vitamin D in these patients had a significant relationship with the response to treatment (P value = 0.004); so that all patients with sufficient vitamin D level had completely recovered, versus 87.5% of patients with vitamin D deficiency and 12.5% of insufficient vitamin D had no response to treatment.

CONCLUSION

According to the results of the present study, the prevalence of vitamin D deficiency in patients with SSNHL was more than healthy people. SSNHL patients with deficient vitamin D had the highest percentage of no response to treatment.

Plasma 25-Hydroxyvitamin D Concentrations Are Inversely Associated with All-Cause Mortality among a Prospective Cohort of Chinese Adults Aged ≥80 Years

BACKGROUND

High concentrations of plasma 25-hydroxyvitamin D [25(OH)D], a marker of circulating vitamin D, have been associated with a lower risk of mortality in epidemiologic studies of multiple populations, but the association for Chinese adults aged ≥80 y (oldest old) remains unclear.

OBJECTIVE

We investigated the association between plasma [25(OH)D] concentration and all-cause mortality among Chinese adults aged ≥80 y.

DESIGN

The present study is a prospective cohort study of 2185 Chinese older adults (median age: 93 y). Prospective all-cause mortality data were analyzed for survival in relation to plasma 25(OH)D using Cox proportional hazards regression models, with adjustments for potential sociodemographic and lifestyle confounders and biomarkers. The associations were measured with HR and 95% CIs.

RESULTS

The median plasma 25(OH)D concentration was 34.4 nmol/L at baseline. Over the 5466 person-year follow-up period, 1100 deaths were identified. Men and women were analyzed together as no effect modification by sex was found. After adjusting for multiple potential confounders, the risk of all-cause mortality decreased as the plasma 25(OH)D concentration increased (P-trend <0.01). Compared with the lowest age-specific quartile of plasma 25(OH)D, the adjusted HRs for mortality for the second, third, and fourth age-specific quartiles were 0.72 (95% CI: 0.57, 0.90), 0.73 (95% CI: 0.58, 0.93), and 0.61 (95% CI: 0.47, 0.81), respectively. The observed associations were broadly consistent across age and other subgroups. Sensitivity analyses generated similar results after excluding participants who died within 2 y of follow-up or after further adjustment for ethnicity and chronic diseases.

CONCLUSIONS

A higher plasma 25-hydroxyvitamin D concentration was associated with a reduced risk of all-cause mortality among Chinese adults aged ≥80 y. This observed inverse association warrants further investigation in randomized controlled trials testing vitamin D supplementation in this age group.

Airway obstruction, serum vitamin D and mortality in a 33-year follow-up study

BACKGROUND AND OBJECTIVE

Chronic obstructive pulmonary disease and low vitamin D status predict mortality, but their combined effect on mortality remains inconclusive. We aimed to investigate a joint effect of airway obstruction and vitamin D status on mortality in a nationally representative cohort.

METHODS

We analysed data of 6676 Finnish adults participating between 1978 and 1980 in a national health examination survey, undergoing spirometry and having all necessary data collected. We followed them up in national registers through record linkage until 31 December 2011. We categorised the subjects with obstruction using the lower limit of normal (LLN) and the measured serum 25-hydroxyvitamin-D (s-25(OH)D) into tertiles.

RESULTS

Both obstruction and low s-25(OH)D independently predicted mortality in a multivariate model adjusted also for age, sex, smoking, education, leisure physical activity, body mass index, asthma and serum C-reactive protein. However, a statistically significant (p = 0.007) interaction emerged: the adjusted mortality HRs (95% CI's) for s-25(OH)D in tertiles among the subjects without and with obstruction were 1.00 (lowest), 0.96 (0.87-1.05) and 0.89 (0.81-0.98); and 1.00, 0.96 (0.71-1.31) and 0.57 (0.40-0.80), respectively.

CONCLUSIONS

In conclusion, obstruction and low s-25(OH)D predict mortality independently of each other. Our findings suggest that low vitamin D status might be particularly detrimental among subjects with obstruction.

No Evidence for Lower Levels of Serum Vitamin D in the Presence of Hepatic Steatosis. A Study on the Portuguese General Population

Introduction and aims: Nonalcoholic fatty liver disease (NAFLD) has become highly prevalent, paralleling the pandemic of obesity and diabetes, and represents an important burden. Nutrition knowledge is fundamental, in prevention, evolution and treatment of NAFLD. Association of low serum levels of vitamin D (VD) with several diseases, including NAFLD, has been emphasized in the last decade. We evaluated how serum levels of VD correlate with the presence of hepatic steatosis, and VD intake, in a random sample of the Portuguese adult population. Methods: Participants underwent a dietary intake inquiry, using a semi-quantitative food frequency questionnaire representative of the usual intake over the previous year. Anthropometric measures, blood tests and ultrasound were done. Hepatic steatosis was quantified according to Hamaguchi's ultrasonographic score (steatosis defined by a score ≥ 2). Results: We recruited 789 adult individuals, 416 males (52.7%), mean age of 49.9 ± 17.0 years (18-79). Prevalence of hepatic steatosis was 35.5%, and after exclusion of excessive alcohol consumption, 28.0%. Mean VD serum levels were 26.0 ± 9.8 ng/ml and 68.4% participants had serum VD levels below 30 ng/ml. Mean serum levels of VD were not significantly different between participants with steatosis vs. no steatosis: 25.2±8.7 vs. 26.4±10.3 ng/ml, respectively (p=0.071). There was no correlation between VD serum levels and VD intake, measured by the FFQ, r=0.075 (p= 0.383). Conclusions: In spite of a high prevalence rate, there was no evidence that decreased VD serum levels were associated with hepatic steatosis. No significant correlation was found between VD dietary ingestion and VD serum levels.

Serum 25-hydroxyvitamin D level, chronic diseases and all-cause mortality in a population-based prospective cohort: the HUNT Study, Norway

OBJECTIVE

To investigate the association of vitamin D status with all-cause mortality in a Norwegian population and the potential influences of existing chronic diseases on the association.

DESIGN

A population-based prospective cohort study.

SETTING

Nord-Trøndelag County, Norway.

PARTICIPANTS

A random sample (n=6613) of adults aged 20 years or older in a cohort.

METHODS

Serum 25-hydroxyvitamin D (25(OH)D) levels were measured in blood samples collected at baseline (n=6377). Mortality was ascertained from the Norwegian National Registry. Cox regression models were applied to estimate the HRs with 95% CIs for all-cause mortality in association with serum 25(OH)D levels after adjustment for a wide spectrum of confounding factors as well as chronic diseases at baseline.

RESULTS

The median follow-up time was 18.5 years, during which 1539 subjects died. The HRs for all-cause mortality associated with the first quartile level of 25(OH)D (<34.5 nmol/L) as compared with the fourth quartile (≥58.1 nmol/L) before and after adjustment for chronic diseases at baseline were 1.30 (95% CI 1.11 to 1.51) and 1.27 (95% CI 1.09 to 1.48), respectively. In the subjects without chronic diseases at baseline and with further exclusion of the first 3 years of follow-up, the corresponding adjusted HR was 1.34 (95% CI 1.09 to 1.66).

CONCLUSIONS

Low serum 25(OH)D level was associated with increased all-cause mortality in a general Norwegian population. The association was not notably influenced by existing chronic diseases.

Circulating 25-hydroxyvitamin D and risk of lung cancer: a dose-response meta-analysis

BACKGROUND

Mounting experimental evidence supports a protective effect of high 25-hydroxyvitamin D (25[OH]D), a good indicator of vitamin D status, on risk of various cancers including lung cancer. However, prospective observational studies examining the 25(OH)D-lung cancer association reported inconsistent findings. A dose-response meta-analysis was carried out to elucidate the subject.

METHODS

Potentially eligible studies were identified by searching PubMed and EMBASE databases, and by carefully reviewing the bibliographies of retrieved publications. The summary relative risks (RRs) with 95% confidence intervals (CIs) were calculated using the random-effects model.

RESULTS

Thirteen reports from ten prospective studies were included, totaling 2,227 lung cancer events. Results of the meta-analysis showed a significant 5% (RR 0.95, 95% CI 0.91-0.99) reduction in the risk of lung cancer for each 10 nmol/L increment in 25(OH)D concentrations. This inverse association was not significantly modified by area, study duration, sex, methods for 25(OH)D measurement, baseline 25(OH)D levels, or quality score of included studies. There was evidence of a nonlinear relationship between 25(OH)D and risk of lung cancer (p-nonlinearity = 0.02), with the greatest reductions in risk observed at 25(OH)D of nearly 53 nmol/L, and remained protective until approximately 90 nmol/L. Further increases showed no significant association with cancer risk, but scanty data were included in the analyses of high-level 25(OH)D. There was no evidence of publication bias.

CONCLUSION

This dose-response meta-analysis of prospective studies suggests that 25(OH)D may be associated with reduced risk of lung cancer, in particular among subjects with vitamin D deficiencies.

Associations of vitamin D deficiency with postoperative gait and mortality among patients with fractures of the proximal femur

Objective

To assess whether serum vitamin D concentration is associated with gait status and mortality among patients with fractures of the proximal femur, six months after suffering the fracture.

Methods

Consecutive patients aged ≥65 years with fractures of the proximal femur, who were admitted to the orthopedics and traumatology ward of our service between January and December 2011, were prospectively evaluated. Clinical, radiological, epidemiological and laboratory analyses were performed, including vitamin D. The patients underwent surgery and were followed up as outpatients, with return visits 15, 30, 60 and 180 days after discharge, at which the outcomes of gait and mortality were evaluated.

Results

Eighty-eight patients were evaluated. Two of them were excluded because they presented oncological fractures. Thus, 86 patients of mean age 80.2 ± 7.3 years were studied. In relation to serum vitamin D, the mean was 27.8 ± 14.5 ng/mL, and 33.7% of the patients presented deficiency of this vitamin. In relation to gait, univariate and multivariate logistic regression showed that vitamin D deficiency was not associated with gait recovery, even after adjustment for gender, age and type of fracture (OR: 1.463; 95% CI: 0.524–4.088; p = 0.469). Regarding mortality, Cox regression analysis showed that vitamin D deficiency was not related to its occurrence within six months, even in multivariate analysis (HR: 0.627; 95% CI: 0.180–2.191; p = 0.465).

Conclusion

Serum vitamin D concentration was not related to gait status and/or mortality among patients with fractures of the proximal femur, six months after suffering the fracture.

Assessment of vibration of effects due to model specification can demonstrate the instability of observational associations

OBJECTIVES

Model specification-what adjusting variables are analytically modeled-may influence results of observational associations. We present a standardized approach to quantify the variability of results obtained with choices of adjustments called the "vibration of effects" (VoE).

STUDY DESIGN AND SETTING

We estimated the VoE for 417 clinical, environmental, and physiological variables in association with all-cause mortality using National Health and Nutrition Examination Survey data. We selected 13 variables as adjustment covariates and computed 8,192 Cox models for each of 417 variables' associations with all-cause mortality.

RESULTS

We present the VoE by assessing the variance of the effect size and in the -log10(P-value) obtained by different combinations of adjustments. We present whether there are multimodality patterns in effect sizes and P-values and the trajectory of results with increasing adjustments. For 31% of the 417 variables, we observed a Janus effect, with the effect being in opposite direction in the 99th versus the 1st percentile of analyses. For example, the vitamin E variant α-tocopherol had a VoE that indicated higher and lower risk for mortality.

CONCLUSION

Estimating VoE offers empirical estimates of associations are under different model specifications. When VoE is large, claims for observational associations should be very cautious.

[Hypovitaminosis D and metabolic syndrome]

Metabolic syndrome and hypovitaminosis D are 2 diseases with high prevalence that share several risk factors, while epidemiological evidence shows they are associated. Although the mechanisms involved in this association are not well established, hypovitaminosis D is associated with insulin resistance, decreased insulin secretion and activation of the renin-angiotensin system, mechanisms involved in the pathophysiology of metabolic syndrome. However, the apparent ineffectiveness of vitamin D supplementation on metabolic syndrome components, as well as the limited information about the effect of improving metabolic syndrome components on vitamin D concentrations, does not clarify the direction and the mechanisms involved in the causal relationship between these 2 pathologies. Overall, because of the high prevalence and the epidemiological association between both diseases, hypovitaminosis D could be considered a component of the metabolic syndrome.

A marriage of two "Methusalem" drugs for the treatment of psoriasis?: Arguments for a pilot trial with metformin as add-on for methotrexate

In this article we present arguments that the “antidiabetic” drug metformin could be useful as an add-on therapy to methotrexate for the treatment of psoriasis and, perhaps, for rheumatoid arthritis as well. Biochemical data suggest that both drugs may share a common cellular target, the AMP-activated protein kinase (AMPK). This enzyme is a master regulator of metabolism and controls a number of downstream targets, e.g., important for cellular growth or function in many tissues including T-lymphocytes. Clinical observations as well as experimental results argue for anti-inflammatory, antineoplastic and antiproliferative activities of metformin and a case-control study suggests that the drug reduces the risk for psoriasis.

Patients with psoriasis have higher risk of metabolic syndrome, type 2 diabetes and cardiovascular mortality. Metformin has proven efficacy in the treatment of prediabetes and leads to a pronounced and sustained weight loss in overweight individuals. We expect that addition of metformin to methotrexate can lead to positive effects with respect to the PASI score, reduction of the weekly methotrexate dose and of elevated cardiovascular risk factors in patients with metabolic syndrome and psoriasis. For reasons explained later we suggest that only male, overweight patients are to be included in a pilot trial. On the other side of the coin are concerns that the gastrointestinal side effects of metformin are intolerable for patients under low dose, intermittent methotrexate therapy. Metformin has another side effect, namely interference with vitamin B₁₂ and folate metabolism, leading to elevated homocysteine serum levels. As patients must receive folate supplementation and will be controlled with respect to their B₁₂ status increased hematological toxicity is unlikely to result.

Meta-analysis of all-cause mortality according to serum 25-hydroxyvitamin D

We examined the relationship between serum 25-hydroxyvitamin D (25[OH]D) and all-cause mortality. We searched biomedical databases for articles that assessed 2 or more categories of 25(OH)D from January 1, 1966, to January 15, 2013. We identified 32 studies and pooled the data. The hazard ratio for all-cause mortality comparing the lowest (0-9 nanograms per milliliter [ng/mL]) to the highest (> 30 ng/mL) category of 25(OH)D was 1.9 (95% confidence interval = 1.6, 2.2; P < .001). Serum 25(OH)D concentrations less than or equal to 30 ng/mL were associated with higher all-cause mortality than concentrations greater than 30 ng/mL (P < .01). Our findings agree with a National Academy of Sciences report, except the cutoff point for all-cause mortality reduction in this analysis was greater than 30 ng/mL rather than greater than 20 ng/mL.

Does low vitamin D amplify the association of COPD with total and cardiovascular disease mortality?

BACKGROUND

Chronic obstructive pulmonary disease (COPD) has been shown to be associated with lower levels of vitamin D, and the latter has been associated with total and cardiovascular disease (CVD) mortality.

HYPOTHESIS

We hypothesized that lower vitamin D levels will further enhance the association of COPD and its severity with total and CVD mortality.

METHODS

We studied 7746 US adults age ≥40 years without known CVD (mean age, 59.8 years) and followed up through 2006 (8.2 ± 2.5 years) for total and CVD mortality. Serum 25-hydroxyvitamin D levels were categorized as tertiles: first tertile, <50.9 nm/L; second tertile, 50.9 to 73.6 nm/L; and third tertile, >73.6 nm/L. Severity of COPD was classified on the basis of forced expiratory volume per second (FEV1 ): mild COPD (FEV1 ≥80%) and moderate or severe COPD (FEV1 <80%), and requires a FEV1 /forced vital capacity ratio <70%. With Cox regression, we examined the hazard ratio (HR) and 95% confidence interval (CI) for total and CVD mortality according to COPD/vitamin D category, using those with no COPD in the first tertile of vitamin D as the reference group.

RESULTS

From Cox regression, unadjusted HRs increased successively with increasing COPD severity and decreasing vitamin D group to 4.5 (95% CI: 3.3-6.1) for total and 3.4 (95% CI: 2.2-5.3) for CVD mortality among those with moderate/severe COPD who were in the first tertile of vitamin D. After adjustment for age, sex, ethnicity, and other risk factors, these associations were attenuated but remained increased.

CONCLUSIONS

Lower levels of vitamin D may be associated with further increases in total and CVD mortality associated with COPD; however, age and cardiovascular risk factors appear to explain much of this association.

Serum 25-hydroxyvitamin D levels and self-reported allergic rhinitis in Norwegian adults - The HUNT Study

BACKGROUND

The role of low vitamin D status in the development of allergic rhinitis is unclear. We aimed to investigate the relationship between serum 25-hydroxyvitamin D [25(OH)D] and incidence of allergic rhinitis in adults.

METHODS

The study included a random sample from an adult population who participated in the second and third surveys of the Nord-Trøndelag Health Study (HUNT) in Norway (HUNT2, 1995-1997 and HUNT3, 2006-2008). Serum 25(OH)D levels were measured in blood samples collected at baseline. Among 1351 adults who did not report allergic rhinitis at baseline, incident allergic rhinitis was identified by participant report of having or having had allergic rhinitis or hay fever at follow-up. Adjusted odds ratios (AOR) and 95% confidence intervals (CI) were calculated after adjustment for age, smoking, physical activity, socioeconomic status, family history of allergy, body mass index, and season. The analyses were stratified by sex due to its significant interaction with 25(OH)D levels (P < 0.02).

RESULTS

Over an average of 11 years, 9% of men and 15% of women developed allergic rhinitis. Among men, serum 25(OH)D level <50 nM was associated with an increased risk of incident allergic rhinitis (AOR 2.55; 95% CI 1.01-6.49); each 25 nM reduction in 25(OH)D level was associated with an AOR of 1.84 (95% CI 1.18-2.87). In women, however, the association was opposite, with AOR being 0.83 (95% CI 0.66-1.05) for each 25 nM reduction in serum 25(OH)D level.

CONCLUSIONS

Vitamin D appears to play different roles in the development of allergic rhinitis among men and women.

Vitamin D deficiency at pediatric intensive care admission

OBJECTIVE

to assess whether 25hydroxivitaminD or 25(OH)vitD deficiency has a high prevalence at pediatric intensive care unit (PICU) admission, and whether it is associated with increased prediction of mortality risk scores.

METHOD

prospective observational study comparing 25(OH)vitD levels measured in 156 patients during the 12 hours after critical care admission with the 25(OH)vitD levels of 289 healthy children. 25(OH)vitD levels were also compared between PICU patients with pediatric risk of mortality III (PRISM III) or pediatric index of mortality 2 (PIM 2) > p75 [(group A; n = 33) vs. the others (group B; n = 123)]. Vitamin D deficiency was defined as < 20 ng/mL levels.

RESULTS

median (p25-p75) 25(OH)vitD level was 26.0 ng/mL (19.2-35.8) in PICU patients vs. 30.5 ng/mL (23.2-38.6) in healthy children (p = 0.007). The prevalence of 25(OH)vitD < 20 ng/mL was 29.5% (95% CI: 22.0-37.0) vs. 15.6% (95% CI: 12.2-20.0) (p = 0.01). Pediatric intensive care patients presented an odds ratio (OR) for hypovitaminosis D of 2.26 (CI 95%: 1.41-3.61). 25(OH)vitD levels were 25.4 ng/mL (CI 95%: 15.5-36.0) in group A vs. 26.6 ng/mL (CI 95%: 19.3-35.5) in group B (p = 0.800).

CONCLUSIONS

hypovitaminosis D incidence was high in PICU patients. Hypovitaminosis D was not associated with higher prediction of risk mortality scores.

Serum 25-hydroxyvitamin D predicts the short-term outcomes of Chinese patients with acute ischaemic stroke

Low vitamin D levels have been reported to contribute to the risk of cardiovascular events and mortality, especially stroke. In the present study we therefore evaluated the short-term prognostic value of serum 25(OH)D (25-hydroxyvitamin D) in Chinese patients with AIS (acute ischaemic stroke). From February 2010 to September 2012, consecutive stroke patients admitted to the emergency department at two hospitals in Beijing, China were identified. Clinical information was collected, and the serum concentration of 25(OH)D and NIHSS (National Institutes of Health Stroke Scale) were measured at the time of admission. Short-term functional outcome was measured using a modified Rankin Scale (mRS) at 90 days after admission. Multivariate analyses were performed using logistic regression models. During the inclusion period, 231 patients were diagnosed as having AIS, and 220 completed follow-up. The median serum 25(OH)D level was significantly lower in patients with AIS compared with normal controls [14.2 (10.2-18.9) ng/ml compared with 17.9 (12.5-22.9) ng/ml; P<0.001; values are medians (interquartile range)]. 25(OH)D was an independent prognostic marker of short-term functional outcome and death {0.79 (0.73-0.85) and 0.70 (0.50-0.98) respectively [values are odds rations (95% confidence intervals)]; P<0.01 for both, adjusted for NHISS, other predictors and vascular risk factors} in patients with AIS. In ROC (receiver operating characteristic) curve analysis, the prognostic accuracy of 25(OH)D was higher compared with all of the other serum predictors and was in the range of NIHSS score. In conclusion, these findings suggest that 25(OH)D is an independent prognostic marker for death and functional outcome within 90 days in Chinese patients with AIS even after adjusting for possible confounding factors.

Does vitamin D sufficiency equate to a single serum 25-hydroxyvitamin D level or are different levels required for non-skeletal diseases?

Objective: Clarify the concept of vitamin D sufficiency, the relationship between efficacy and vitamin D status and the role of Vitamin D supplementation in the management of non-skeletal diseases. We outline reasons for anticipating different serum vitamin D levels are required for different diseases. Method: Review the literature for evidence of efficacy of supplementation and minimum effective 25-hydroxyvitamin D (25-OHD) levels in non-skeletal disease. Results: Evidence of efficacy of vitamin supplementation is graded according to levels of evidence. Minimum effective serum 25-OHD levels are lower for skeletal disease, e.g., rickets (25 nmol/L), osteoporosis and fractures (50 nmol/L), than for premature mortality (75 nmol/L) or non-skeletal diseases, e.g., depression (75 nmol/L), diabetes and cardiovascular disease (80 nmol/L), falls and respiratory infections (95 nmol/L) and cancer (100 nmol/L). Conclusions: Evidence for the efficacy of vitamin D supplementation at serum 25-OHD levels ranging from 25 to 100 nmol/L has been obtained from trials with vitamin D interventions that change vitamin D status by increasing serum 25-OHD to a level consistent with sufficiency for that disease. This evidence supports the hypothesis that just as vitamin D metabolism is tissue dependent, so the serum levels of 25-OHD signifying deficiency or sufficiency are disease dependent.

Vitamin D status and childhood health

Vitamin D is an essential component of bone and mineral metabolism; its deficiency causes growth retardation and skeletal deformities in children and osteomalacia and osteoporosis in adults. Hypovitaminosis D (vitamin D insufficiency or deficiency) is observed not only in adults but also in infants, children, and adolescents. Previous studies suggest that sufficient serum vitamin D levels should be maintained in order to enhance normal calcification of the growth plate and bone mineralization. Moreover, emerging evidence supports an association between 25-hydroxyvitamin D (25[OH]D) levels and immune function, respiratory diseases, obesity, metabolic syndrome, insulin resistance, infection, allergy, cancers, and cardiovascular diseases in pediatric and adolescent populations. The risk factors for vitamin D insufficiency or deficiency in the pediatric population are season (winter), insufficient time spent outdoors, ethnicity (non-white), older age, more advanced stage of puberty, obesity, low milk consumption, low socioeconomic status, and female gender. It is recommended that all infants, children, and adolescents have a minimum daily intake of 400 IU (10 µg) of vitamin D. Since the vitamin D status of the newborn is highly related to maternal vitamin D levels, optimal vitamin D levels in the mother during pregnancy should be maintained. In conclusion, given the important role of vitamin D in childhood health, more time spent in outdoor activity (for sunlight exposure) and vitamin D supplementation may be necessary for optimal health in infants, children, and adolescents.

Vitamin D and subsequent all-age and premature mortality: a systematic review

Background

All-cause mortality in the population < 65 years is 30% higher in Glasgow than in equally deprived Liverpool and Manchester. We investigated a hypothesis that low vitamin D in this population may be associated with premature mortality via a systematic review and meta-analysis.

Methods

Medline, EMBASE, Web of Science, the Cochrane Library and grey literature sources were searched until February 2012 for relevant studies. Summary statistics were combined in an age-stratified meta-analysis.

Results

Nine studies were included in the meta-analysis, representing 24,297 participants, 5,324 of whom died during follow-up. The pooled hazard ratio for low compared to high vitamin D demonstrated a significant inverse association (HR 1.19, 95% CI 1.12-1.27) between vitamin D levels and all-cause mortality after adjustment for available confounders. In an age-stratified meta-analysis, the hazard ratio for older participants was 1.25 (95% CI 1.14-1.36) and for younger participants 1.12 (95% CI 1.01-1.24).

Conclusions

Low vitamin D status is inversely associated with all-cause mortality but the risk is higher amongst older individuals and the relationship is prone to residual confounding. Further studies investigating the association between vitamin D deficiency and all-cause mortality in younger adults with adjustment for all important confounders (or using randomised trials of supplementation) are required to clarify this relationship.

Is there a reverse J-shaped association between 25-hydroxyvitamin D and all-cause mortality? Results from the U.S. nationally representative NHANES

CONTEXT

A reverse J-shaped association between serum 25-hydroxyvitamin D (25[OH]D) concentration and all-cause mortality was suggested in a 9-year follow-up (1991-2000) analysis of the Third National Health and Nutrition Examination Survey (NHANES III, 1988-1994).

OBJECTIVE

Our objective was to repeat the analyses with 6 years additional follow-up to evaluate whether the association persists through 15 years of follow-up.

PARTICIPANTS

The study included 15 099 participants aged ≥ 20 years with 3784 deaths.

MAIN OUTCOME MEASURE

Relative risk (RR) of death from all causes was adjusted for age, sex, race/ethnicity, and season using 2 Poisson regression approaches: traditional categorical and cubic splines. Results were given for 9 25(OH)D levels: <20, 20 to 29, 30 to 39, 40 to 49, 50 to 59, 60 to 74, 75 to 99 (reference), 100 to 119, and ≥ 120 nmol/L.

RESULTS

The reverse J-shaped association became stronger with longer follow-up and was not affected by excluding deaths within the first 3 years of follow-up. Similar results were found from both statistical approaches for levels <20 through 119 nmol/L. Adjusted RR (95% confidence interval [CI]) estimates for all levels <60 nmol/L were significantly >1 compared with the reference group. The nadir of risk was 81 nmol/L (95% CI, 73-90 nmol/L). For 25(OH)D ≥ 120 nmol/L, results (RR, 95% CI) were slightly different using traditional categorical (1.5, 1.02-2.3) and cubic splines approaches (1.2, 0.9-1.4). The association appeared in men, women, adults ages 20 to 64 years, and non-Hispanic whites but was weaker in older adults. The study was too small to evaluate the association in non-Hispanic black and Mexican-American adults.

CONCLUSIONS

A reverse J-shaped association between serum 25(OH)D and all-cause mortality appears to be real. It is uncertain whether the association is causal.

Vitamin D status and incident cardiovascular disease and all-cause mortality: a general population study

Low vitamin D status has been associated with cardiovascular disease (CVD) and mortality primarily in selected groups, smaller studies, or with self-reported vitamin D intake. We investigated the association of serum vitamin D status with the incidence of a registry-based diagnosis of ischemic heart disease (IHD), stroke, and all-cause mortality in a large sample of the general population. A total of 9,146 individuals from the two population-based studies, Monica10 and Inter99, were included. Measurements of serum 25-hydroxyvitamin D at baseline were carried out using the IDS ISYS immunoassay system in Monica10 and High-performance liquid chromatography in Inter99. Information on CVDs and causes of death was obtained from Danish registries until 31 December 2008. There were 478 cases of IHD, 316 cases of stroke, and 633 deaths during follow-up (mean follow-up 10 years). Cox regression analyses with age as underlying time axis showed a significant association between vitamin D status and all-cause mortality with a HR = 0.95 (P = 0.005) per 10 nmol/l higher vitamin D level. We found no association between vitamin D status and incidence of IHD or stroke (HR = 1.01, P = 0.442 and HR = 1.00, P = 0.920, respectively). In this large general population study, the observed inverse association between serum vitamin D status and all-cause mortality was not explained by a similar inverse association with IHD or stroke.

[Calcium supplementation and the possible increase in cardiovascular risk]

The primary goal of osteoporosis treatment is to prevent the occurrence of fragility fractures, and thereby reduce morbidity and mortality. Among the various approaches to the treatment of this disease include ensuring proper calcium intake and to obtain adequate levels of vitamin D. Virtually all clinical trials with drugs used to treat osteoporosis systematically include calcium and vitamin D supplements. In light of the recent publication of clinical trials and meta-analyses, a possible increase in cardiovascular risk, particularly in the form of a myocrdial infarction, is hypothesised in patients taking calcium supplements. However, data published to date are inconclusive. Until the development of new scientific evidence, it seems reasonable to recommend, whenever practicable and individualized for each patient, increasing calcium intake with food and reserve supplements for patients with very low calcium intake in the diet. It would also be advisable for the administration of total daily dose to be fractionated throughout the day and with meals, and to obtain appropriate levels of vitamin D (25-hydroxycholecalciferol or calcidiol), along with the basic treatment for osteoporosis that is decided to be prescribed to patients.

Serum 25-hydroxyvitamin D levels and incident asthma in adults: the HUNT Study

The impact of low vitamin D status on asthma development is unclear. The authors investigated the relation between the baseline serum 25-hydroxyvitamin D (25(OH)D) level and incident asthma in adults, including possible effect modification by allergy status, using allergic rhinitis as a proxy measure. A cohort of 25,616 Norwegian adults aged 19-55 years participated in 2 surveys of the Nord-Trøndelag Health Study known as HUNT 2 (1995-1997) and HUNT 3 (2006-2008). Of this cohort, a nested case-control study included 584 new-onset asthma cases and 1,958 nonasthma controls whose baseline serum 25(OH)D levels were measured. After adjustment for potential asthma risk factors, the baseline serum level of 25(OH)D (<50 nmol/L) was not significantly associated with asthma in either women (adjusted odds ratio = 0.94, 95% confidence interval (CI): 0.67, 1.32) or men (adjusted odds ratio = 1.47, 95% CI: 0.93, 2.32). In men, allergic rhinitis modified the association with the adjusted odds ratio being 0.87 (95% CI: 0.36, 2.06) among men with allergic rhinitis and 2.32 (95% CI: 1.06, 5.10) among men without allergic rhinitis. The serum 25(OH)D level was not associated with incident asthma in women, regardless of allergy status. Low vitamin D status was not significantly associated with incident asthma in most adults, but it may have increased risk among men without allergy.

The risk of all-cause mortality is inversely related to serum 25(OH)D levels

CONTEXT AND OBJECTIVES

Vitamin D plays a key role in maintaining bone health, but evidence for its nonskeletal effects is inconsistent. This study aims to examine the association between serum 25-hydroxyvitamin D [25(OH)D] levels and all-cause mortality in a large general population cohort.

DESIGN, PARTICIPANTS, AND SETTING

Using the computerized database of the largest health care provider in Israel, we identified a cohort of subjects 20 years old or older with serum 25(OH)D levels measured between January 2008 and December 2009. Vital status was ascertained through August 2011.

RESULTS

Median follow-up was 28.5 months (interquartile range 23.8-33.5 months); 7,247 of 182,152 participants (4.0%) died. Subjects who died had significantly lower serum 25(OH)D levels (mean 44.8 ± 24.2 nmol/liter) than those alive at the end of follow-up (51.0 ± 23.2 nmol/liter), P < 0.001. After adjustment for age, gender, ethnicity, and seasonality, the hazard ratio (HR) for all-cause mortality was 2.02 [95% confidence interval (CI) 1.89-2.15] for the lowest serum 25(OH)D quartile (<33.8 nmol/liter) compared with the highest. After further adjustment for comorbidity, use of vitamin D supplements and statins, smoking, socioeconomic status, and body mass index, the HR was 1.81 (95% CI 1.69-1.95). This remained, even after adjustment for serum low-density lipoprotein, high-density lipoprotein, calcium level (corrected for serum albumin levels), and glomerular filtration rate, 1.85 (95% CI 1.70-2.01). The fully adjusted HR associated with being in the second 25(OH)D quartile (33.8-49.4 nmol/liter) was 1.25 (95% CI 1.16-1.34).

CONCLUSIONS

All-cause mortality is independently and inversely associated with serum 25(OH)D levels at levels less than 50 nmol/liter.

[Vitamin D: pathophysiology and clinical applicability in paediatrics]

Vitamin D has always been associated with calcium -phosphate metabolism, but vitamin D receptors or its metabolites have been found in different body cells, indicating a possible involvement in other physiological mechanisms. Vitamin D deficiency has been associated with an increased risk of infections, autoimmune diseases, diabetes, metabolic syndrome, obesity, asthma and certain neurological diseases such as schizophrenia. Currently there are different techniques for measuring 25 (OH) cholecalciferol in blood, but the results are variable and controversial. It is important to achieve standardization of these techniques to be able to compare the results obtained in different studies. Normal physiological vitamin D levels have not yet been established, but they must be higher than 20 ng/ml (50 nmol/l) in order to perform it physiological function. It is still under discussion on how to achieve these minimum levels. Since the main source of vitamin D is sunlight, we should look for strategies that do not contradict the messages of prevention of skin cancer. In recent years, recommendations for vitamin D intake have changed, involving prophylactic activities carried out in Primary Care. This manuscript reviews the physiology, actions, laboratory determination, desirable levels, and vitamin D intake recommendations, and it highlights many questions raised by new research.

The longitudinal variability of serum 25(OH)D levels

BACKGROUND

The extent to which a single serum 25(OH)D measurement represents long-term vitamin D status remains unclear. This study aims to assess the variability of serum 25(OH)D between tests taken at different time intervals.

METHODS

Using the computerized database of the largest healthcare provider in Israel, we identified subjects in whom a serum 25(OH)D test was performed on at least two different occasions between January 2008 and September 2011 (n = 188,771). For these subjects we selected the first and the last dated tests, then we identified those who were not treated with supplements during the last 6 months before the first and before the last test (n = 94,418). Of these we analyzed subjects in whom the first and the last tests were performed in the same month of the year (n = 8881).

RESULTS

The mean serum 25(OH)D level at the first test was 51.7 ± 24.0 nmol/L and was 56.7 ± 24.7 at the last test (P<0.001); the overall correlation was 0.63 (P < 0.001). For vitamin D status in two categories (<50 versus ≥ 50 nmol/L), the percentage of agreement between the first and last tests was 74.4%, and was 50.8% for vitamin D status in four categories (<30, 30-49.9, 50-74.9, and ≥ 75 nmol/L). The correlation decreased with increasing time between the tests ranging from 0.83 for tests done at the same year to 0.55 after 3 years. The more the first levels were higher or lower, the more likely subjects remain in their first category (≥ 50 versus <50 nmol/L).

CONCLUSIONS

Long-term month specific serum 25(OH)D levels are relatively stable.

Cross-sectional and prospective cohort study of serum 25-hydroxyvitamin D level and obesity in adults: the HUNT study

Experimental studies suggest that vitamin D modulates the activity of adipocytes. The authors examined baseline serum 25-hydroxyvitamin D (25(OH)D) level in relation to prevalent and cumulative incident obesity in Norway. A cohort of 25,616 adults aged 19-55 years participated in both the second and third surveys of the Nord-Trøndelag Health Study (HUNT 2 (1995-1997) and HUNT 3 (2006-2008)). Serum 25(OH)D levels measured at baseline and anthropometric measurements taken at both baseline and follow-up were available for a random sample of 2,460 subjects. Overall, 40% of the 2,460 subjects had a serum 25(OH)D level less than 50.0 nmol/L, and 37% had a level of 50.0-74.9 nmol/L. The prevalence and cumulative incidence of obesity, defined as body mass index (weight (kg)/height (m)(2)) ≥30, were 12% and 15%, respectively. Lower serum 25(OH)D level was associated with a higher prevalence of obesity. In the 2,165 subjects with baseline BMI less than 30, a serum 25(OH)D level less than 50.0 nmol/L was associated with a significantly increased odds ratio for incident obesity during follow-up (adjusted odds ratio = 1.73, 95% confidence interval: 1.24, 2.41). When prevalent and incident obesity were classified according to waist circumference (≥88 cm for women, ≥102 cm for men), similar results were obtained. In addition to prevalent obesity, a serum 25(OH)D level less than 50.0 nmol/L was significantly associated with new-onset obesity in adults.

Serum 25-hydroxyvitamin D levels and all-cause and cardiovascular disease mortality among US adults with hypertension: the NHANES linked mortality study

OBJECTIVES

Research suggests that serum concentrations of 25-hydroxyvitamin D [25(OH)D] are inversely associated with hypertension incidence. This study examined whether concentrations of 25(OH)D are inversely associated with mortality risk among US adults with hypertension.

METHODS

We analyzed data from the 2001-2004 National Health and Nutrition Examination Survey with mortality data obtained through 2006. Hazard ratios with 95% confidence intervals (CIs) for all-cause and cardiovascular disease (CVD) mortality were estimated using Cox proportional hazard models.

RESULTS

Of 2609 participants with hypertension, 191 died (including 68 CVD deaths) during an average of 3.7-year follow-up. Compared with participants with 25(OH)D concentrations in the highest quartile (≥29 ng/ml), the hazard ratios for all-cause mortality were 1.93 (95% CI 1.06-3.49), 1.32 (95% CI 0.85-2.04), and 1.36 (95% CI 0.84-2.22), respectively (P for trend <0.05), and the hazard ratios for CVD mortality were 3.21 (95% CI 1.14-8.99), 2.42 (95% CI 0.85-6.90), and 2.33 (95% CI 0.88-6.12), respectively (P for trend <0.05), in the first (<17 ng/ml), second (17-<23 ng/ml) and third (23-<29 ng/ml) quartiles of 25(OH)D after adjustment for potential confounding variables. Additionally, concentrations of 25(OH)D as a continuous variable were linearly and inversely associated with the risk of mortality from all causes (P = 0.012) and from CVD (P = 0.010). These relationships were not affected much by adjustment for baseline blood pressure and use of antihypertension medications.

CONCLUSION

Concentrations of 25(OH)D were inversely associated with all-cause and CVD mortality among adults with hypertension in the US. Enhancing vitamin D intake may contribute to a lower risk for premature death.

Vitamin D status among 4-month-old infants in New England: a prospective cohort study

BACKGROUND

Concerns over vitamin D deficiency in infants and children recently prompted the American Academy of Pediatrics to recommend increased supplementation. Few studies have examined vitamin D status in the same infants over time. Also, while many researchers label "breastfeeding" as a risk factor for vitamin D deficiency, few differentiate between any breastfeeding, exclusive breastfeeding, and supplemented or unsupplemented breastfeeders.

OBJECTIVE

To determine predictors of 25(OH)D deficiency at 4 months in a group of children previously tested at birth.

METHODS

We enrolled newborns from 2005 to 2007 at an urban Boston hospital. Maternal and infant blood samples were collected within 72 hours of birth. At 4 months, we obtained a second infant blood sample.

RESULTS

At 4 months, 11.9% of the 177 infants were vitamin D deficient compared to 37.5% at birth (25(OH)D <20 ng/mL). Median 25(OH)D was 35.2 ng/mL (range, 5-100.8; 95% confidence interval [CI], 32.8-37.6). At 4 months, 40% of unsupplemented infants were deficient. Lack of supplementation was significantly associated with increased risk of deficiency (adjusted odds ratio [AOR], 19.3; 95% CI, 4.80-77.2). Being outside at least 10 minutes a day, once per week, was protective (AOR, 0.12; 95% CI, 0.02-0.66), as was increasing gestational age (AOR, 0.36; 95% CI, 0.19-0.69). In 48.4% of patients, physicians failed to prescribe vitamin D at 2 months.

CONCLUSIONS

Despite inconsistent supplementation, a smaller proportion of infants were vitamin D deficient at 4 months than at birth. While supplemented breastfed infants were not at risk of deficiency, unsupplemented exclusively breastfed infants were at high risk of severe deficiency.