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

Saturation association between serum 25-hydroxyvitamin D levels and mortality in elderly people with hyperlipidemia: a population-based study from the NHANES (2001-2016)

Background

25-hydroxyvitamin D is the body's main storage form of vitamin D and is internationally recognized as the best indicator of vitamin D status in the human body. There is a scarcity of research investigating the interrelationship between serum 25-hydroxyvitamin D (25(OH)D) levels and mortality among elderly individuals with hyperlipidemia. To address this knowledge gap, we examined the association between serum 25(OH)D levels and mortality in an older hyperlipidemic population from NHANES, while controlling for other influential factors. The study sought to elucidate the correlation between serum 25(OH)D levels and mortality about all-cause mortality, cardiovascular disease (CVD), malignant neoplasms, and mortality from other causes.

Methods

The data from NHANES 2001-2016, including 9,271 participants were analyzed to examine the association between serum 25(OH)D levels and mortality. The interrelationship was illustrated using Kaplan-Meier curves and restricted cubic splines, while the Cox proportional hazards model was utilized to estimate the multifactor adjusted hazard ratio (HR).

Results

This study included 9,271 participants (43.28% male) with an average age of 69.58 years, and the average duration of participant follow-up was 88.37 months. Kaplan-Meier curves demonstrated that lower serum 25(OH)D levels were associated with increased risks of all-cause mortality, cardiovascular mortality, malignant neoplasm mortality, and mortality from other causes. This negative association was further confirmed by the Cox proportional hazards models. Additionally, restricted cubic splines not only revealed this negative association but also highlighted the saturated serum 25(OH)D levels. Moreover, subgroup analyses indicated that the inverse correlation between serum 25(OH)D levels and all-cause mortality was more pronounced in the non-obese and smoking population. And the inverse correlation with mortality from other causes was even stronger in the non-obese population.

Conclusions

In the elderly population with hyperlipidemia, 25(OH)D serum levels were negatively correlated with both cause-specific mortality and all-cause mortality. Moreover, there was a threshold effect in this negative association.

C-reactive protein-albumin-lymphocyte index as a feasible nutrition-immunity-inflammation marker of the outcome of all-cause and cardiovascular mortality in elderly

BACKGROUND & AIMS

The imbalance of nutrition-immunity-inflammation status might be associated with the mortality risk in the elderly. This study aimed to assess the relationship between the C-reactive protein (CRP)-albumin-lymphocyte (CALLY) index and all-cause and cardiovascular disease (CVD) mortality in the elderly.

METHODS

The data from records of older adults (≥ 60 years) were derived from 1999 to 2010 and 2015-2018 National Health and Nutrition Examination Survey. Weighted Cox proportional hazard regression was used to analyze the relationship between CALLY and all-cause mortality and CVD mortality in three different models, and the linear trend was analyzed. A restricted cubic spline model was used to evaluate the nonlinear dose-response relationship and determine the critical threshold of CALLY to divide the population into two groups. Kaplan-Meier analysis and log-rank test were used to evaluate the cumulative survival rates of different groups. Subgroup analyses and sensitivity analyses were performed to ensure robustness.

RESULTS

Compared to the first quartile of natural log-transformation (ln) CALLY, the highest quartile of ln CALLY was negatively correlated with the risk of all-cause mortality (HR = 0.67, 95% CI: 0.56-0.79. P < 0.05) and CVD mortality (HR = 0.65, 95% CI: 0.47-0.89. P < 0.05) in model 3. Ln CALLY was linear dose-response correlated with mortality. We determined that the critical threshold for ln CALLY in elderly was 1.00. Elderly with higher ln CALLY (≥ 1.00) had significantly increased survival rates (P < 0.05).

CONCLUSION

CALLY showed a significant negative linear association with the risk of all-cause mortality and CVD mortality, and higher CALLY was beneficial to the survival outcomes of the elderly.

Relationship between dietary protein, serum albumin, and mortality in asthmatic populations: a cohort study

Background

Currently, there is limited research on the correlation between protein levels in the body and asthma. We used data from the NHANES to explore the relationship of dietary protein, serum albumin, with mortality in individuals with asthma to better understand their impact on asthma.

Method

This investigation involved 3005 individuals with asthma from the NHANES dataset. Studying potential links between dietary protein, serum albumin, and mortality in asthmatic populations utilized the Cox proportional hazards models, trend test, restricted cubic splines (RCS), and Kaplan-Meier survival analysis. Furthermore, subgroup analyses were carried out to explore these connections within specific populations.

Result

After considering all potential variables, multivariate Cox proportional hazard models proved that dietary protein intake did not have an independent connection with all-cause mortality, but serum albumin was inversely linked with all-cause mortality. Each unit rise in serum albumin (g/l) was linked to a 13% decrease in the likelihood of all-cause mortality. RCS confirmed a negative and linear connection of serum albumin with all-cause mortality. The Kaplan-Meier survival curve suggested that asthmatic adults with greater serum albumin levels had a decreased risk of mortality compared to those with lower levels.

Conclusion

The investigation proved a negative linear connection of serum albumin with all-cause mortality in asthma patients. However, there was no independent link discovered between dietary protein intake with mortality. This indicates that serum albumin could be a significant factor in predicting long-term outcomes for asthma patients.

Associations of serum albumin and dietary protein intake with all-cause mortality in community-dwelling older adults at risk of sarcopenia

Objective

The Asian Working Group for Sarcopenia 2019 consensus emphasized nutritional assessment and intervention for community-dwelling older people with sarcopenia status. This study aimed to examine the association of serum albumin and dietary protein intake (DPI) with all-cause mortality among older adults at risk of sarcopenia.

Methods

We enrolled 1763 older adults at risk of sarcopenia in the Chinese Longitudinal Healthy Longevity Survey (2012-2018) using calf circumference and handgrip strength. Serum albumin concentrations were measured using bromocresol green methods, and DPI frequency was evaluated using a semi-quantitative questionnaire at baseline. Cox proportional hazards models were used to explore the association of serum albumin and DPI with all-cause mortality.

Results

During 5606.3 person-years of follow-up (median: 3.28 years), 802 older people died. After adjusting for socio-demographics, health behaviors, and clinical characteristics, we observed an inverse linear association between serum albumin and all-cause mortality (Pnon-linear = 0.429). Participants with low albumin levels (<40.0 g/L) had a 43 % higher risk of mortality than their counterparts (hazard ratio (HR) = 1.43, 95 % confidence interval (CI) = 1.22-1.66). There was no significant association between DPI and mortality (Ps > 0.05). Moreover, the association between low albumin and all-cause mortality remained significant in the lower DPI subgroup (HR = 1.47, 95 % CI = 1.18-1.85), but was not significant in the high DPI subgroup (HR = 1.15, 95 % CI = 0.92-1.39).

Conclusions

Serum albumin levels are inversely associated with all-cause mortality in community-based older adults at risk of sarcopenia. Sufficient dietary protein consumption may attenuate the effect of low serum albumin on increased mortality and potential mechanisms for the interaction warrant further exploration.

Interaction between handgrip strength and vitamin D deficiency on all-cause mortality in community-dwelling older adults: a prospective cohort study

OBJECTIVE

Muscle strength decline and vitamin D deficiency are coexisting conditions associated with multiple adverse health outcomes. This prospective study aimed to investigate the multiplicative and additive interactions between handgrip strength (HS) and serum 25-hydroxyvitamin D [25(OH)D] on all-cause mortality in Chinese community-dwelling older adults.

STUDY DESIGN

This is a population-based cohort study.

METHODS

2635 older adults (85.15 ± 12.01 years) were recruited from the Chinese Longitudinal Healthy Longevity Survey (2012-2018). Low HS was defined according to the Asian Working Group for Sarcopenia 2019 updated consensus (<28 kg for men and <18 kg for women). Serum 25(OH)D < 50 nmol/L were defined as vitamin D deficiency. Cox proportional hazard models were used to examine the association of HS and 25(OH)D with all-cause mortality. Socio-demographics, health status, and clinical characteristics were included as covariates.

RESULTS

1715 (65.09 %) and 1885 (71.54 %) participants had low HS and vitamin D deficiency, respectively. During a median follow-up of 3.52 years, 1107 older people died. After multivariable adjustment, both HS and 25(OH)D levels were inversely associated with all-cause mortality risk (Ps < 0.001). The hazard ratios (HRs) of low HS and vitamin D deficiency for all-cause mortality were 1.73 (95 % CI: 1.41-2.13) and 1.61 (95 % CI: 1.32-1.93), respectively. Although significant multiplicative interactions were not found, the association between low HS and all-cause mortality was attenuated in the higher 25(OH)D subgroup than in the lower 25(OH)D subgroup (stratified by 50 nmol/L). The multiple-adjusted HR of mortality for combined low HS and vitamin D deficiency was 2.18 (95 % CI: 1.73-2.56), which was higher than that for these two conditions alone. Significant additive interactions between low HS and vitamin D deficiency on mortality were observed (relative excess risk due to interaction: 0.71, 95 % CI: 0.37-1.05).

CONCLUSIONS

Low HS and low 25(OH)D levels synergistically increased the risk of all-cause mortality. Our results added new insights to the priority of early detection for older adults with comorbid muscle strength decline and vitamin D deficiency.

Combined effects of vitamin D deficiency and systemic inflammation on all-cause mortality and cause-specific mortality in older adults

BACKGROUND

Vitamin D deficiency and systemic inflammation share common pathological mechanisms in muscle loss, cardio-pulmonary function decline, and abnormal metabolism, which are linked to chronic conditions, senescence, and early mortality. However, their combined effect on mortality in older adults has not been well established. This study longitudinal aimed to explore the independent and combined associations of serum 25-hydroxyvitamin D [25(OH)D] and high sensitivity C-reactive protein (hs-CRP) with mortality risk in Chinese community-based older people.

METHODS

3072 older adults (86.07 ± 11.87 years, 54.52% female) from the Chinese Longitudinal Healthy Longevity Survey (2012-2018) were enrolled. Baseline 25(OH)D and hs-CRP levels were collected, and survival information was recorded in the 2014 and 2018 follow-up waves. Cox proportional hazard regressions were conducted to explore the associations between 25(OH)D, hs-CRP, and mortality. Demographic characteristics, health behaviors, and chronic disease biomarkers were adjusted.

RESULTS

During 10,622.3 person-years of follow-up (median: 3.51 years), 1321 older adults died, including 448 deaths due to cardiovascular disease (CVD). Increased mortality risk was associated with lower 25(OH)D and higher hs-CRP quantiles, even after adjusting for each other and multiple covariates (all P-trend < 0.05). In combined analyses, the highest all-cause mortality (HR: 2.18, 95% CI: 1.73 ~ 2.56), CVD mortality (HR: 2.30, 95% CI: 1.64 ~ 3.21), and non-CVD mortality (HR: 2.19, 95% CI: 1.79 ~ 2.49) were obtained in participants with both 25(OH)D deficiency (< 50 nmol/L) and high hs-CRP (≥ 3.0 mg/L), respectively. We observed significant additive interactions of 25(OH)D and hs-CRP on all-cause mortality and non-CVD mortality (RERIS>0).

CONCLUSIONS

Low 25(OH)D and high hs-CRP, both independently and jointly, increase mortality risk in Chinese community-dwelling older adults. Thus, priority should be given to early detection and appropriate intervention in older individuals with combined vitamin D deficiency and systemic inflammation. Molecular mechanisms of related adverse health effect are worthy of further investigation.

Multiple cardiometabolic diseases enhance the adverse effects of hypoalbuminemia on mortality among centenarians in China: a cohort study

BACKGROUND

Although hypoalbuminemia was associated with high risk of mortality in community-dwelling older adults, as well as in the hospitalized older adults, little is known among centenarians. And there are limited data on whether having cardiometabolic diseases (CMDs) is associated with additive effects.

METHODS

Baseline examinations including a determination of albumin levels were performed in 1002 Chinese centenarians from January 2014 through to December 2016, and the survival status was subsequently ascertained until 31 May 2021. Cox proportional risk model was performed to assess the risk of all-cause mortality associated with albumin levels and hypoalbuminemia combined with CMDs.

RESULTS

Of 1002 participants included in the analysis, the mean level of albumin was 38.5 g/L (± standard deviation, 4.0 g/L), and 174 (17.4%) had hypoalbuminemia (albumin < 35 g/L). The multivariable analyses showed that albumin level was negatively associated with all-cause mortality (Ptrend < 0.05). Compared to normoalbuminemia, hypoalbuminemia was associated with an increased mortality risk in the overall participants (hazard ratio [HR]: 1.55, 95% confidence interval [CI]: 1.22-1.97). Furthermore, the HR (95% CI) of hypoalbuminemia combined with multiple CMDs was 2.15 (1.14-4.07). There was evidence of an additive deleterious dose effect of an increasing number of CMDs (Ptrend = 0.001).

CONCLUSIONS

Hypoalbuminemia is associated with an increased risk of all-cause mortality in Chinese centenarians, and this risk is more pronounced among centenarians with multiple cardiometabolic diseases. Our findings suggest that older adults with hypoalbuminemia, especially comorbid multiple CMDs warrant early identification and management.

Biomarkers of aging

Aging biomarkers are a combination of biological parameters to (i) assess age-related changes, (ii) track the physiological aging process, and (iii) predict the transition into a pathological status. Although a broad spectrum of aging biomarkers has been developed, their potential uses and limitations remain poorly characterized. An immediate goal of biomarkers is to help us answer the following three fundamental questions in aging research: How old are we? Why do we get old? And how can we age slower? This review aims to address this need. Here, we summarize our current knowledge of biomarkers developed for cellular, organ, and organismal levels of aging, comprising six pillars: physiological characteristics, medical imaging, histological features, cellular alterations, molecular changes, and secretory factors. To fulfill all these requisites, we propose that aging biomarkers should qualify for being specific, systemic, and clinically relevant.

Does Albumin Predict the Risk of Mortality in Patients with Cardiogenic Shock?

This study investigates the prognostic impact of albumin levels in patients with cardiogenic shock (CS). Intensive care unit (ICU) related mortality in CS patients remains unacceptably high despite improvement concerning the treatment of CS patients. Limited data regarding the prognostic value of albumin in patients with CS is available. All consecutive patients with CS from 2019 to 2021 were included at one institution. Laboratory values were retrieved from the day of disease onset (day 1) and days 2, 3, 4, and 8 thereafter. The prognostic impact of albumin was tested for 30-day all-cause mortality. Moreover, the prognostic performance of albumin decline during ICU treatment was examined. Statistical analyses included univariable t-test, Spearman's correlation, Kaplan-Meier analyses, multivariable mixed analysis of variance (ANOVA), C-Statistics, and Cox proportional regression analyses. In total, 230 CS patients were included, with an overall all-cause mortality at 30 days of 54%. The median albumin on day 1 was 30.0 g/L. Albumin on day 1 was able to discriminate between 30-day survivors and non-survivors (area under the curve (AUC) 0.607; 0.535-0.680; p = 0.005). CS patients with albumin < 30.0 g/L were associated with an increased risk of 30-day all-cause mortality (63% vs. 46%; log-rank p = 0.016; HR = 1.517; 95% CI 1.063-2.164; p = 0.021), which was demonstrated even after multivariable adjustment. Moreover, a decrease of albumin levels by ≥20% from day 1 to day 3 was accompanied by a higher risk of 30-days all-cause mortality (56% vs. 39%; log-rank p = 0.036; HR = 1.645; 95% CI 1.014-2.669; p = 0.044). Especially when combined with lactate, creatinine, and cardiac troponin I, reliable discrimination of 30-day all-cause mortality was observed, including albumin in CS risk stratification models (AUC = 0.745; 95% CI 0.677-0.814; p = 0.001). In conclusion, low baseline albumin levels as well as a decay of albumin levels during the course of ICU treatment, deteriorate prognostic outcomes in CS patients. The additional assessment of albumin levels may further improve risk stratification in CS patients.

Associations of Serum 25(OH)D, PTH, and β-CTX Levels with All-Cause Mortality in Chinese Community-Dwelling Centenarians

This longitudinal cohort study explored the associations of 25-hydroxyvitamin D [25(OH)D], parathyroid hormone (PTH), and β-C-terminal telopeptide of type 1 collagen (β-CTX) levels with all-cause mortality in centenarians. The study included 952 centenarians (81.4% female). During a median follow-up of 32 months, 752 (78.9%) centenarians died. The estimated 1-year, 3-year, and 5-year survival rates were 80.0%, 45.7%, and 23.6%, respectively. The association of mortality with 25(OH)D was linear, whereas the associations with PTH and β-CTX were J-shaped, with a lower risk below the median levels. Compared with 25(OH)D of ≥30 ng/mL, 25(OH)D < 30 ng/mL was associated with increased mortality (HR 1.52, 95% CI 1.24−1.86, p < 0.001). Compared with PTH of ≤65 pg/mL, PTH > 65 pg/mL was associated with increased mortality (HR 1.30, 95% CI 1.08−1.56, p = 0.005). Compared with β-CTX of <0.55 ng/mL, β-CTX ≥ 0.55 ng/mL was associated with increased mortality (HR 1.30, 95% CI 1.10−1.54, p = 0.002). A higher β-CTX level (even in the clinical reference range of 0.55−1.01 ng/mL) was associated with increased mortality (HR 1.23, 95% CI 1.04−1.47, p = 0.018). Centenarians with 25(OH)D < 30 ng/mL, PTH > 65 pg/mL, and β-CTX ≥ 0.55 ng/mL had a 2.77-fold (95% CI 1.99−3.85, p < 0.001) increased risk of mortality when compared with those with 25(OH)D of >30 ng/mL, PTH < 65 pg/mL, and β-CTX < 0.55 ng/mL. Lower serum 25(OH)D and higher PTH and β-CTX were independently correlated with increased all-cause mortality in Chinese community-dwelling centenarians.

A machine learning-based data mining in medical examination data: a biological features-based biological age prediction model

Background

Biological age (BA) has been recognized as a more accurate indicator of aging than chronological age (CA). However, the current limitations include: insufficient attention to the incompleteness of medical data for constructing BA; Lack of machine learning-based BA (ML-BA) on the Chinese population; Neglect of the influence of model overfitting degree on the stability of the association results.

Methods and results

Based on the medical examination data of the Chinese population (45–90 years), we first evaluated the most suitable missing interpolation method, then constructed 14 ML-BAs based on biomarkers, and finally explored the associations between ML-BAs and health statuses (healthy risk indicators and disease). We found that round-robin linear regression interpolation performed best, while AutoEncoder showed the highest interpolation stability. We further illustrated the potential overfitting problem in ML-BAs, which affected the stability of ML-Bas’ associations with health statuses. We then proposed a composite ML-BA based on the Stacking method with a simple meta-model (STK-BA), which overcame the overfitting problem, and associated more strongly with CA (r = 0.66, P < 0.001), healthy risk indicators, disease counts, and six types of disease.

Conclusion

We provided an improved aging measurement method for middle-aged and elderly groups in China, which can more stably capture aging characteristics other than CA, supporting the emerging application potential of machine learning in aging research.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12859-022-04966-7.

Associations of Serum Albumin With Disability in Activities of Daily Living, Mobility and Objective Physical Functioning Regardless of Vitamin D: Cross-Sectional Findings From the Chinese Longitudinal Healthy Longevity Survey

Objective

To examine the associations of serum albumin, a nutrition indicator, with disability in activities of daily living (ADL), mobility, and objective physical functioning among Chinese older adults.

Materials and Methods

Cross-sectional data of 2233 older adults (≥65 years) who participated in the 2011/2012 main survey of the Chinese Longitudinal Healthy Longevity Survey (CLHLS) and the 2012 biomarker sub-study was used. Serum albumin was measured by immunoturbidimetric assay. Physical functioning included subjectively (ADL and mobility) and objectively measured disability (standing up from a chair, picking up a book from the floor, and turning around 360°). Multivariable logistic regression models were performed.

Results

After adjusting for age and sex, compared with participants in the lowest quartile group of serum albumin, those in the highest quartile group had 45% lower odds of disability in ADL (odds ratio [OR]: 0.55; 95% confidence interval [CI]: 0.38, 0.80); 48% lower odds of disability in mobility (OR: 0.52; 95% CI: 0.38, 0.71); 46% lower odds of disability in standing up from a chair (OR: 0.54; 95% CI: 0.34, 0.85); and 37% lower odds of disability in picking up a book from the floor (OR: 0.63; 95% CI: 0.40, 0.97). We did not observe a statistically significant interaction effect between serum albumin and vitamin D on disability in physical functioning.

Conclusion

Serum albumin level was associated with physical functioning among Chinese older adults, regardless of vitamin D level. The findings indicate that appropriate management of poor nutritional status, in particular low serum albumin levels, may contribute to maintaining physical functioning in older adults.

The long-term prognostic value of serum 25(OH)D, albumin, and LL-37 levels in acute respiratory diseases among older adults

Background

Older adults are more susceptible to respiratory tract infection than healthy working age adults. The increased susceptibility of older adults is thought to be interlinked with vitamin D status, nourishment, and immunological state in general. Data are scarce whether these parameters could serve as prognostic markers.

Aim

To study whether serum 25(OH)D, albumin, and LL-37 level could give prognostic value of long-term survival in the older adults with multimorbidity and acute respiratory infection.

Methods

Consecutive episodes of hospital care of patients 65 years and older with respiratory symptoms were prospectively studied as a cohort. Standard clinical questionnaire was filled by the study physician. Laboratory markers included serum levels of 25(OH)D, albumin and LL-37, C-reactive protein (CRP), white blood cell count (WBC) and polymerase chain reaction diagnostics for 14 respiratory viruses. Pneumonia was confirmed by chest radiographs. Respiratory illness severity, death at ward, length of hospital stays, and 5-year survival were used as outcomes.

Results

In total, 289 older adult patients with mean age of 83 years were included in the study. Serum 25(OH)D deficiency (< 50 nmol/liter) was present in 59% and hypoalbuminemia (< 3.5 g/dL) in 55% of the study patients. Low serum albumin level was associated to one, two- and five-year mortality after hospital stay (all P < .05). In addition, it was associated with pneumonia, dyspnea, over 13-night long stay at ward and death at ward (all P < .05). No associations were seen between serum 25(OH)D and LL-37 levels and disease severity, short-term clinical outcome, or long-term survival. Associations between serum 25(OH)D, albumin, and LL-37 levels and respiratory virus presence were not seen.

Conclusions

Serum albumin level on admission seems to give valuable information about the patients’ general health and recovery potential in treating older adults with respiratory symptoms. Serum 25(OH)D and LL-37 had no associations with disease severity or long- and short-term prognosis among older adults hospitalized with respiratory symptoms.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-02836-8.

A Machine Learning-Based Aging Measure Among Middle-Aged and Older Chinese Adults: The China Health and Retirement Longitudinal Study

Objective: Biological age (BA) has been accepted as a more accurate proxy of aging than chronological age (CA). This study aimed to use machine learning (ML) algorithms to estimate BA in the Chinese population. Materials and methods: We used data from 9,771 middle-aged and older Chinese adults (≥45 years) in the 2011/2012 wave of the China Health and Retirement Longitudinal Study and followed until 2018. We used several ML algorithms (e.g., Gradient Boosting Regressor, Random Forest, CatBoost Regressor, and Support Vector Machine) to develop new measures of biological aging (ML-BAs) based on physiological biomarkers. R-squared value and mean absolute error (MAE) were used to determine the optimal performance of these ML-BAs. We used logistic regression models to examine the associations of the best ML-BA and a conventional aging measure-Klemera and Doubal method-BA (KDM-BA) we previously developed-with physical disability and mortality, respectively. Results: The Gradient Boosting Regression model performed the best, resulting in an ML-BA with an R-squared value of 0.270 and an MAE of 6.519. This ML-BA was significantly associated with disability in basic activities of daily living, instrumental activities of daily living, lower extremity mobility, and upper extremity mobility, and mortality, with odds ratios ranging from 1 to 7% (per 1-year increment in ML-BA, all P < 0.001), independent of CA. These associations were generally comparable to that of KDM-BA. Conclusion: This study provides a valid ML-based measure of biological aging for middle-aged and older Chinese adults. These findings support the application of ML in geroscience research and may help facilitate preventive and geroprotector intervention studies.

Effect of Exercise Training on 1,25(OH)2D Levels: The FIT-AGEING Randomized Controlled Trial

BACKGROUND

Vitamin D deficiency is currently endemic worldwide and is considered as an important factor in the development of several chronic conditions. Physical exercise has been postulated as an auspicious strategy to counteract age-related disorders preventing premature mortality. However, the effects of chronic exercise training on 1,25-dihydroxyvitamin D [1,25(OH)₂D] is unclear. This 12-week randomized controlled trial aimed to investigate the effects of different training modalities on 1,25(OH)₂D in healthy sedentary adults.

HYPOTHESIS

Exercise training will increase 1,25(OH)₂D in the study cohort.

STUDY DESIGN

Randomized controlled clinical trial.

LEVEL OF EVIDENCE

Level 1.

METHODS

A total of 89 healthy sedentary adults (53% women; 53.5 ± 4.9 years old) were enrolled in the FIT-AGEING study. The participants were randomized to (1) a control group (no exercise), (2) physical activity recommendation from the World Health Organization (PAR group), (3) high-intensity interval training (HIIT group), and (4) HIIT adding whole-body electromyostimulation training (HIIT + EMS). 1,25(OH)₂D plasma levels were measured using a DiaSorin Liaison immunochemiluminometric analyzer.

RESULTS

Compared with the control group, 1,25(OH)₂D increased in PAR (Δ = 10.99 ± 3.44 pg/mL; P = 0.01), HIIT (Δ = 11.63 ± 3.51 pg/mL; P = 0.009), and HIIT + EMS groups (Δ = 14.01 ± 3.59 pg/mL; P = 0.001) without statistical differences between them (all Ps > 0.1).

CONCLUSION

In summary, the results show that a 12-week exercise intervention produced an increment of 1,25(OH)₂D independently of age, sex, and exercise modality in healthy sedentary adults.

CLINICAL RELEVANCE

The implementation of physical exercise could be considered a strategy not only aiming to reverse the seasonal decrease of 1,25(OH)₂D in winter explained by low sunlight exposure but also for obtaining subsequent increases of this hormone even in these a priori adverse conditions.

The establishment of serum 25-hydroxyvitamin D reference intervals in children aged 0-14 years in Zigong area, China

OBJECTIVE

To establish the reference interval of serum 25-hydroxyvitamin D (25(OH)D) in apparently healthy children in Zigong, China, using an indirect method to provide a basis for proper clinical diagnosis and treatment.

METHODS

A total of 1851 apparently healthy children of the Children's Health Care Department in Zigong First People's Hospital between January 2016 and December 2020 were included in the study. The Kolmogorov-Smirnov test was used to analyze the data for normality, and the non-normally distributed data were transformed into approximately normal distribution by Blom's normal rank transformation, and the transformed data were excluded from outliers by the quartile spacing method, and the data were stratified and analyzed according to sex, age, and season. The data were stratified according to sex, age, and season, and the area between the 2.5% and 97.5% percentile points was used as the reference interval.

RESULTS

The serum 25(OH)D data were non-normally distributed. The data were normally distributed after Blom's normality rank transformation, and 92 cases of outliers were excluded from the transformed data according to the interquartile spacing method. The differences in serum 25(OH)D levels between sex were not statistically significant (P > 0.05), and there was no need to establish reference intervals based on sex. There was no statistically significant difference in serum 25-hydroxyvitamin D levels between winter and spring, and also no difference between summer and autumn (P > 0.05), and the levels were lower in winter-spring than in summer-autumn. Comparison between age groups showed that there was no statistically significant difference in serum 25(OH)D levels between the < 6 months group and the 6 ~ 11 months group, and between the 6 ~ 9 years group and the 10 ~ 14 years group (P > 0.05); serum 25(OH)D levels decreased with increasing age. There was an interactive effect of season and age group on 25(OH)D levels, and the corresponding reference intervals were established according to different seasons and age groups. In summer and autumn, the reference intervals of serum 25(OH)D for < 1 year, 1 ~ 2 years, 3 ~ 5 years, and 6 ~  14 years were 39.86 ~ 151.43, 31.54 ~ 131.65, 22.05 ~ 103.75, and 15.36 ~ 85.53 ng/ml and 24.42 ~ 144.20, 31.54 ~ 131.65, 16.80 ~ 165.68, and 15.46 ~ 85.54 ng/ml in winter and spring, respectively.

CONCLUSION

Reference intervals for serum 25(OH)D in children of different seasons and ages in Zigong, China, were established to provide a reference for clinical disease diagnosis, treatment, and prognosis determination.

Vitamin D in autophagy signaling for health and diseases: Insights on potential mechanisms and future perspectives

Vitamin D regulates the pleiotropic effect to maintain cellular homeostasis and epidemiological evidence establishes an association between vitamin D deficiency and various human diseases. Here, the role of autophagy, the cellular self-degradation process, in vitamin D-dependent function is documented in different cellular settings and discussed the molecular aspects for treating chronic inflammatory, infectious diseases, and cancer. Vitamin D activates autophagy through a genomic and non-genomic signaling pathway to influence a wide variety of physiological functions of different body organs along with bone health and calcium metabolism. Moreover, it induces autophagy as a protective mechanism to inhibit oxidative stress and apoptosis to regulate cell proliferation, differentiation, and immune modulation. Furthermore, vitamin D and its receptor regulate autophagy signaling to control inflammation and host immunity by activating antimicrobial defense mechanisms. Vitamin D has been revealed as a potent anticancer agent and induces autophagy to increase the response to radiation and chemotherapeutic drugs for potential cancer therapy. Increasing vitamin D levels in the human body through timely exposure to sunlight or vitamin D supplements could activate autophagy as part of the homeostasis mechanism to prevent multiple human diseases and aging-associated dysfunctions.

Serum 25-Hydroxyvitamin D and Subsequent Cancer Incidence and Mortality: A Population-Based Retrospective Cohort Study

OBJECTIVE

To determine the relationship between 25-hydroxyvitamin D (25[OH]D) values and subsequent cancer incidence and mortality.

PATIENTS AND METHODS

We identified all adult patients living in Olmsted County, Minnesota, between January 1, 2005, and December 31, 2011, who had at least 1 25(OH)D measurement and no prior diagnosis of cancer. Cancer outcomes were retrieved starting 30 days after 25(OH)D measurement and until patients' final clinical visit as an Olmsted County resident; December 31, 2014; or death. Cox proportional hazards regression was used to analyze data.

RESULTS

A total of 8700 individuals had a 25(OH)D measurement and no history of cancer, with a mean ± SD 25(OH)D value of 29.7±12.8 ng/mL (to convert to nmol/L, multiply by 2.496). The mean ± SD age was 51.5±16.4 years, and most were women (78.1%; n=6796) and White (85.7%; n=7460). A total of 761 individuals developed cancer (skin cancer, n=360; nonskin cancer, n=401) during a median follow-up of 4.6 (interquartile range, 3.4-6.1) years. Compared with participants with 25(OH)D values of 20 to 50 ng/mL (reference group), those with 25(OH)D values less than 12 ng/mL had a greater nonskin cancer incidence (hazard ratio [HR], 1.56; 95% CI, 1.03 to 2.36; P=.04) after adjustment. There was no association between 25(OH)D values and total cancer or skin cancer incidence. Compared with individuals from the reference group, 25(OH)D levels less than 12 ng/mL (HR, 2.35; 95% CI, 1.01 to 5.48; P=.047) and 12 to 19 ng/mL (HR, 2.10; 95% CI, 1.05 to 4.22; P=.04) were associated with increased cancer mortality.

CONCLUSION

Low 25(OH)D levels were associated with increased risk for incident nonskin cancer and cancer-related mortality.

Relationship of sedentary time, physical activity and fitness with 1,25-dihydroxyvitamin D in middle-aged sedentary adults: The FIT-AGEING study

PURPOSE

Potential interactions between sedentary behaviour, physical activity (PA), and physical fitness with 25-hydroxyvitamin D (25(OH)D) status have been previously suggested. However, data are scarce concerning the association between these predictors of general health and the main active metabolite of vitamin D, the 1,25-dihidroxyvitamin D (1,25(OH)₂D). This study aimed to analyse the relationship of sedentary time, PA levels, and physical fitness (i.e., maximal oxygen uptake (VO₂max) and muscular strength) with 1,25(OH)₂D in middle-aged sedentary adults.

METHODS

A total of 73 (39 women) middle-aged sedentary adults (53.7 ± 5.1 years old) participated in this cross-sectional study. Sedentary time and PA intensity levels were objectively measured with triaxial accelerometers for 7 consecutive days. VO₂max was determined by a maximum treadmill test. Lower and upper limb muscular strength was assessed by an isokinetic strength test and by a handgrip strength test, respectively. 1,25(OH)₂D plasma levels were measured using a DiaSorin Liaison® immunochemiluminometric assay.

RESULTS

No significant relationships were found between objectively measured sedentary time, PA levels or physical fitness (i.e., VO₂max, extension and flexion peak torque, and hand grip strength) and 1,25(OH)₂D (all P > 0.05). All results persisted after controlling for age, sex, fat mass or energy, vitamin D, calcium, and phosphorus intake.

CONCLUSIONS

In summary, our results show that vitamin D status is not affected by physical activity habits and sedentary behaviour in middle-aged sedentary adults.

Associations Between Complement Components and Vitamin D and the Physical Activities of Daily Living Among a Longevous Population in Hainan, China

Background: Vitamin D and complement components shared some common pathophysiological pathways in the musculoskeletal system, circulation, and metabolism, which were linked to physical function. It is hypothesized that serum complement components may interact with vitamin D in respect of the physical activities of daily living (PADLs). Objective: To investigate if serum complement components 3 (C3), complement components 4 (C4), and 25-hydroxyvitamin D [25(OH)D] associate with PADLs, and to examine whether the association between 25(OH)D levels and PADLs varies at different complement component levels among Chinese centenarians. Methods: This study was conducted in a group of population-based centenarians. PADLs were evaluated using the Barthel Index. Multiple regressions were used to analyze the associations among 25(OH)D, complements C3 and C4, and PADLs. Results: Among 943 participants, 672 (71.3%) had physical dependence (PD). After adjusting for potential confounders, serum 25(OH)D and C3 levels were positively correlated with PADLs, while C4 levels were negatively correlated with PADLs (Ps < 0.05). Serum 25(OH)D levels significantly interacted with both C3 (P for interaction = 0.033) and C4 (P for interaction = 0.006) levels on PADLs. At lower complement component levels, the multivariate odds ratios (ORs) of the upper tertile of vitamin D for PD were 0.32 (95% CI: 0.18-0.55) in the C3 group and 0.29 (95% CI: 0.16-0.50) in the C4 group. At higher complement component levels, the ORs in the C3 and C4 groups were not statistically significant. Conclusions: In a group of population-based Chinese centenarians, we observed that serum complement C3 and 25(OH)D levels were positively associated with PADLs, while C4 was negatively associated with PADLs. The associations between 25(OH)D levels and PADLs were more pronounced in groups with lower serum complement component levels.