Hasil untuk "Nutritional diseases. Deficiency diseases"

Haidong Wang, M. Naghavi, Christine Allen et al.

BACKGROUND Improving survival and extending the longevity of life for all populations requires timely, robust evidence on local mortality levels and trends. The Global Burden of Disease 2015 Study (GBD 2015) provides a comprehensive assessment of all-cause and cause-specific mortality for 249 causes in 195 countries and territories from 1980 to 2015. These results informed an in-depth investigation of observed and expected mortality patterns based on sociodemographic measures. METHODS We estimated all-cause mortality by age, sex, geography, and year using an improved analytical approach originally developed for GBD 2013 and GBD 2010. Improvements included refinements to the estimation of child and adult mortality and corresponding uncertainty, parameter selection for under-5 mortality synthesis by spatiotemporal Gaussian process regression, and sibling history data processing. We also expanded the database of vital registration, survey, and census data to 14 294 geography-year datapoints. For GBD 2015, eight causes, including Ebola virus disease, were added to the previous GBD cause list for mortality. We used six modelling approaches to assess cause-specific mortality, with the Cause of Death Ensemble Model (CODEm) generating estimates for most causes. We used a series of novel analyses to systematically quantify the drivers of trends in mortality across geographies. First, we assessed observed and expected levels and trends of cause-specific mortality as they relate to the Socio-demographic Index (SDI), a summary indicator derived from measures of income per capita, educational attainment, and fertility. Second, we examined factors affecting total mortality patterns through a series of counterfactual scenarios, testing the magnitude by which population growth, population age structures, and epidemiological changes contributed to shifts in mortality. Finally, we attributed changes in life expectancy to changes in cause of death. We documented each step of the GBD 2015 estimation processes, as well as data sources, in accordance with Guidelines for Accurate and Transparent Health Estimates Reporting (GATHER). FINDINGS Globally, life expectancy from birth increased from 61·7 years (95% uncertainty interval 61·4-61·9) in 1980 to 71·8 years (71·5-72·2) in 2015. Several countries in sub-Saharan Africa had very large gains in life expectancy from 2005 to 2015, rebounding from an era of exceedingly high loss of life due to HIV/AIDS. At the same time, many geographies saw life expectancy stagnate or decline, particularly for men and in countries with rising mortality from war or interpersonal violence. From 2005 to 2015, male life expectancy in Syria dropped by 11·3 years (3·7-17·4), to 62·6 years (56·5-70·2). Total deaths increased by 4·1% (2·6-5·6) from 2005 to 2015, rising to 55·8 million (54·9 million to 56·6 million) in 2015, but age-standardised death rates fell by 17·0% (15·8-18·1) during this time, underscoring changes in population growth and shifts in global age structures. The result was similar for non-communicable diseases (NCDs), with total deaths from these causes increasing by 14·1% (12·6-16·0) to 39·8 million (39·2 million to 40·5 million) in 2015, whereas age-standardised rates decreased by 13·1% (11·9-14·3). Globally, this mortality pattern emerged for several NCDs, including several types of cancer, ischaemic heart disease, cirrhosis, and Alzheimer's disease and other dementias. By contrast, both total deaths and age-standardised death rates due to communicable, maternal, neonatal, and nutritional conditions significantly declined from 2005 to 2015, gains largely attributable to decreases in mortality rates due to HIV/AIDS (42·1%, 39·1-44·6), malaria (43·1%, 34·7-51·8), neonatal preterm birth complications (29·8%, 24·8-34·9), and maternal disorders (29·1%, 19·3-37·1). Progress was slower for several causes, such as lower respiratory infections and nutritional deficiencies, whereas deaths increased for others, including dengue and drug use disorders. Age-standardised death rates due to injuries significantly declined from 2005 to 2015, yet interpersonal violence and war claimed increasingly more lives in some regions, particularly in the Middle East. In 2015, rotaviral enteritis (rotavirus) was the leading cause of under-5 deaths due to diarrhoea (146 000 deaths, 118 000-183 000) and pneumococcal pneumonia was the leading cause of under-5 deaths due to lower respiratory infections (393 000 deaths, 228 000-532 000), although pathogen-specific mortality varied by region. Globally, the effects of population growth, ageing, and changes in age-standardised death rates substantially differed by cause. Our analyses on the expected associations between cause-specific mortality and SDI show the regular shifts in cause of death composition and population age structure with rising SDI. Country patterns of premature mortality (measured as years of life lost [YLLs]) and how they differ from the level expected on the basis of SDI alone revealed distinct but highly heterogeneous patterns by region and country or territory. Ischaemic heart disease, stroke, and diabetes were among the leading causes of YLLs in most regions, but in many cases, intraregional results sharply diverged for ratios of observed and expected YLLs based on SDI. Communicable, maternal, neonatal, and nutritional diseases caused the most YLLs throughout sub-Saharan Africa, with observed YLLs far exceeding expected YLLs for countries in which malaria or HIV/AIDS remained the leading causes of early death. INTERPRETATION At the global scale, age-specific mortality has steadily improved over the past 35 years; this pattern of general progress continued in the past decade. Progress has been faster in most countries than expected on the basis of development measured by the SDI. Against this background of progress, some countries have seen falls in life expectancy, and age-standardised death rates for some causes are increasing. Despite progress in reducing age-standardised death rates, population growth and ageing mean that the number of deaths from most non-communicable causes are increasing in most countries, putting increased demands on health systems. FUNDING Bill & Melinda Gates Foundation.

Esther M. Choo, Christopher G. Kemp, K. C. Sagun et al.

Abstract Limited evidence exists on the costs of scaled‐up multisectoral nutrition programmes. Such evidence is crucial to assess intervention value and affordability. Evidence is also lacking on the opportunity costs of implementers and participants engaging in community‐level interventions. We help to fill this gap by estimating the full financial and economic costs of the United States Agency for International Development‐funded Suaahara II (SII) programme, a scaled‐up multisectoral nutrition programme in Nepal (2016–2023). We applied a standardized mixed methods costing approach to estimate total and unit costs over a 3.7‐year implementation period. Financial expenditure data from national and subnational levels were combined with economic cost estimates assessed using in‐depth interviews and focus group discussions with staff, volunteers, community members, and government partners in four representative districts. The average annual total cost was US$908,948 per district, with economic costs accounting for 47% of the costs. The annual unit cost was US$132 per programme participant (mother in the 1000‐day period between conception and a child's second birthday) reached. Annual costs ranged from US$152 (mountains) to US$118 (plains) per programme participant. Personnel (63%) were the largest input cost driver, followed by supplies (11%). Community events (29%) and household counselling visits (17%) were the largest activity cost drivers. Volunteer cadres contributed significant time to the programme, with female community health volunteers spending a substantial amount of time (27 h per month) on SII activities. Multisectoral nutrition programmes can be costly, especially when taking into consideration volunteer and participant opportunity costs. This study provides much‐needed evidence of the costs of scaled‐up multisectoral nutrition programmes for future comparison against benefits.

Zhaoting Bu, Zhiyong Li, Xiaoyue Liu et al.

Abstract Background The EAT-Lancet Commission proposed the Planetary Health Diet to improve both human and planetary health. Evidence among older adults on its association with mortality and cardiovascular disease (CVD) remains limited. We therefore examined associations of the Planetary Health Diet Index (PHDI) with risks of all-cause mortality and CVD in a representative sample of U.S. middle-aged and older adults. Methods This cohort study used data from the U.S. Health and Retirement Study (HRS; 2012–2018) with dietary intake data from the 2013 Health Care and Nutrition Study (HCNS). Adherence to the PHDI was computed from 24-hour dietary recalls across 15 food groups (score range 0–140). All-cause mortality was ascertained via household surveys, and incident cardiovascular disease (CVD) was identified by self-reported physician-diagnosed heart disease. Cox proportional hazards models estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between quintiles of PHDI and risks of mortality and CVD, adjusting for demographic, lifestyle, and health-related covariates, including total energy intake. Results The total cohort included 7,873 participants (58.83% women; mean age 66.72 years) for the mortality analysis, and the sub-cohort included 5,454 participants (60.80% women; mean age 64.65 years) for the cardiovascular disease analysis. Higher PHDI adherence was associated with lower risks of total mortality. Participants in the highest PHDI quintile had a 59% lower risk of total mortality compared with those in the lowest quintile (HRs: 0.41; 95% CI: 0.32, 0.53). Each 1 SD increase in PHDI was associated with a 25% reduction in all-cause mortality (HRs: 0.75; 95% CI: 0.69, 0.81). PHDI was also inversely associated with CVD risk (HRs: 0.72; 95% CI: 0.58, 0.91). Conclusions In this cohort of U.S. older adults, higher adherence to the PHDI was associated with lower risks of all-cause mortality and cardiovascular disease.

Pengyu Wang, Li Huang, Zhou Zhu et al.

Abstract Background Hypertension and type 2 diabetes are major global health burdens and often coexist due to shared metabolic risk factors. Relative muscle strength (RMS), a composite measure of muscle function, shows an inverse association with hypertension. The mechanisms underlying this link remain unclear. Elevated fasting blood glucose (FBG) reflects impaired glucose metabolism and insulin resistance and is associated with both reduced muscle strength and higher blood pressure. This suggests that FBG may partly mediate the RMS–hypertension relationship. Yet, large-scale population studies have rarely tested this mediating pathway, leaving an important knowledge gap. Methods We analyzed data from two nationally representative cohorts: NHANES (2011–2014;adults aged ≥ 18 Years, mean age 48 years ) and CHARLS (2011–2012; adults aged ≥ 45 Years, mean age 58 years). Hypertension prevalence was nearly 30.0% in NHANES and 42.1% in CHARLS. RMS was calculated as grip strength divided by appendicular skeletal muscle mass (ASM). Hypertension was defined as systolic/diastolic blood pressure ≥ 140/90 mmHg or self-reported diagnosis. Logistic regression examined the RMS–hypertension associations, and causal mediation analysis quantified fasting glucose’s mediating role, and restricted cubic spline models were applied to explore potential non-linear relationship. Results In NHANES (n = 9,652; Hypertension prevalence 30.0%), RMS was inversely associated with hypertension across quartiles (Q2–Q4 vs. Q1: adjusted ORs (95% CIs) of 0.82, 0.78, and 0.72, respectively). Mediation analysis showed fasting glucose partially mediated this association, accounting for 13.1% of this association. In CHARLS (n = 12,946; Hypertension prevalence 42.1%), similar trends were observed (Q2–Q4 vs. Q1: adjusted ORs (95% CIs) 0.91, 0.76, and 0.66), But fasting glucose partially mediated this association, explaining only 2.0% of the association. Restricted cubic spline models revealed significant nonlinearity in CHARLS (P < 0.001) but not in NHANES (P = 0.921). Conclusion This study is the first to examine the partially mediating role of fasting blood glucose in the RMS–hypertension relationship across diverse populations. RMS was consistently associated with lower hypertension risk, with varying degrees of glucose mediation between cohorts. These findings support integrating RMS assessment into cardiovascular risk screening and highlight muscle strength as a potential target for non-pharmacological prevention. Given the cross-sectional nature of this study, longitudinal research is needed to clarify causal pathways and inform public health strategies.

Kendall E Brand, Jessica Danh, Cameron Mccarthy et al.

Makenzie A Tharpe, Abigail L Zirbel, Joanna L Fiddler

Daniel Robinson, Ann Kan, Lauren Bonner et al.

Imteaz Mahmud, Benjamin Guesdon, Marko Kerac et al.

Abstract Small and nutritionally at‐risk infants aged under 6 months (<6 months) are at high risk of death, but important evidence gaps exist on how to best identify them. We aimed to determine associations between anthropometric deficits and mortality among infants <6 months admitted to inpatient therapeutic care. A secondary analysis of 2002–2008 data included 5034 infants aged <6 months from 12 countries. We estimated the prevalence, concurrence, and severity of wasted, stunted, and underweight, as stand‐alone indicators, and using the Composite Index of Anthropometric Failure (CIAF), which combines these indicators into six subgroups of single and multiple anthropometric deficits and into one combined indicator called CIAF. We used logistic regression to examine the association of different anthropometric deficits with in‐programme mortality. Among 3692 infants aged <6 months with complete data, 3539 (95.8%) were underweight, 3058 (82.8%) were wasted, 2875 (77.8%) were stunted and 3575 (96.8%) had CIAF. Infants with multiple anthropometric deficits were presented with significantly lower anthropometric indices, that is, they were more severely wasted, stunted and underweight. A total of 141 infants died during inpatient therapeutic care. Among these, severely wasted (116) and severely underweight (138) infants had higher odds of mortality than normal infants (odds ratio [OR] = 2.1, 95% confidence interval [CI]: 1.2–2.7, p = 0.009, and OR = 3.3, 95% CI: 0.8–13.6, p = 0.09, respectively). Boys had higher odds of inpatient mortality than girls (OR = 1.40, 95% CI: 1.02–1.92, p = 0.03). Mortality was only observed in infants <6 months presenting multiple anthropometric deficits, although their odds of mortality were not significant, for example, OR = 2.4, 95% CI: 0.5–10.0, p = 0.21 for stunted, wasted and underweight infants <6 months. In conclusion, multiple anthropometric deficits (CIAF) is common among infants <6 months and may be reported in nutrition care programmes and surveys. Both weight‐for‐length/height z‐score and weight‐for‐age z‐score were found to be useful indicators for programme admission and in‐programme prognosis. Future work needs to explore which better accounts for admission bias. Boys appear to be most at‐risk of dying while receiving malnutrition therapeutic care. Programmes should ensure that all infants receive timely, evidence‐based, effective care.

Haijun Wan, Nuo Xu, Lijuan Wang et al.

Abstract Background Considering the increasing prevalence of obesity/overweight, its treatment or prevention with new interventions can greatly help health and reduce its adverse effects in people. One of these new interventions is investigating the effect of Survodutide as a dual agonist of glucagon and GLP-1 receptors, which seems to be able to influence weight loss processes in different ways. In this study, we investigated the effect of injectable Survodutide on weight loss. Methods In order to identify all randomized controlled trials that investigated the effects of Survodutide on factores related to obesity, a systematic search was conducted in the original databases using predefined keywords until August 2024. The pooled weighted mean difference and 95% confidence intervals were computed using the random-effects model. Results The Findings from 18 treatment arms with 1029 participants indicated significant reductions in weight (WMD: -8.33 kg; 95% CI: -10.80, -5.86; I2 = 99.6%), body mass index (BMI) (WMD:-4.03 kg/m2; 95% CI: -4.86, -3.20; I2 = 72.7%), and waist circumferences (WC) (WMD: -6.33 cm; 95% CI: -8.85 to -3.81; I2 = 99.5%) following the Survodutide injection compared to the control group. Subgroup analysis reveals that longer interventions (more than 16 weeks) and higher doses (more than 2 mg/week) of Survodutide are associated with more significant reductions in weight and WC. These results were also observed in the meta-regression analysis. Conclusions The results of this meta-analysis show that Survodutide is effective in reducing weight, BMI and waist circumference, especially with longer interventions and higher doses.

Xiaoxin Zhou, Xiaoqian Lin, Jing Yu et al.

Abstract Background Time-restricted eating (TRE), a popular form of intermittent fasting, has shown benefits for improving metabolic diseases and cardiometabolic health. However, the effect of TRE in the regulation of blood pressure in primary hypertension remains unclear. Methods A 6-week randomized controlled trial was conducted, in which a total of 74 stage 1 primary hypertensive patients without high-risk were randomly assigned to Dietary Approaches to Stop Hypertension (DASH) group (n = 37) or DASH + TRE group (n = 37). Participants in the DASH + TRE group were instructed to consume their food within an 8-h window. Scientific research platform in We Chat application was used to track participants. The primary outcome was blood pressure. The secondary outcomes included body composition, cardiometabolic risk factors, inflammation-related parameters, urinary Na+ excretion, other clinical variables and safety outcomes. Results The reduction of systolic blood pressure and diastolic blood pressure were 5.595 ± 4.072 and 5.351 ± 5.643 mm Hg in the DASH group and 8.459 ± 4.260 and 9.459 ± 4.375 mm Hg in the DASH + TRE group. DASH + TRE group improved blood pressure diurnal rhythm. Subjects in DASH + TRE group had decreased extracellular water and increased urinary Na+ excretion. Furthermore, the decrease in blood pressure was associated with a reduction of extracellular water or increase in urinary Na+ excretion. In addition, safety outcomes such as nighttime hunger were also reported. Conclusion Our study demonstrated that 8-h TRE + DASH diet caused a greater decrease in blood pressure in stage 1 primary hypertensive patients than DASH diet. This study may provide novel insights into the benefits of lifestyle modification in the treatment of primary hypertension. Trial registration https://www.chictr.org.cn/ (ChiCTR2300069393, registered on March 15, 2023).

Jessica M. White, Elizabeth Drummond, Vasundhara Bijalwan et al.

Abstract The complementary feeding period is a critical stage of child development when micronutrient needs are high and challenging to meet. Understanding if specific micronutrient gaps exist during this period is critical for effective programming. A Comprehensive Nutrient Gap Assessment (CONGA) was conducted in seven countries in Southeast Asia to estimate gaps in micronutrients commonly lacking in the diets of children aged 6–23 months and to establish the certainty of available evidence for each identified gap. Sixty‐eight evidence sources were identified during this analysis, and 310 micronutrient‐specific data points were identified across all seven countries. Data points varied in recency, representativeness and evidence type. The CONGA methodology enabled the estimation of a gap burden rating for each micronutrient in each country, as well as a rating of their evidence certainty. Micronutrient gaps were identified in vitamin D, zinc and iron and a potential gap was identified in calcium during the complementary feeding period in the region. Evidence relevant to intake and deficiency of folate, vitamin B12, thiamine, niacin, vitamin C and vitamin B6 was limited across the region. Proven strategies to address these gaps include increasing the availability and consumption of nutrient‐dense foods, micronutrient supplementation, large‐scale fortification of staple foods and condiments and point‐of‐use fortification through multiple micronutrient powders and fortified speciality foods. More recent data on micronutrient availability, intake and deficiency is urgently needed in Southeast Asia.

Srishti Mediratta, Santu Ghosh, Pulkit Mathur

Abstract Objective: This study assessed diet diversity and consumption of ultra-processed foods and explored its impact on macronutrient intake and risk of micronutrient inadequacy. Design: Cross-sectional, non-probability snowball sampling. Setting: Nutrient intake was assessed using 24-h dietary recall method and diet diversity through FAO-diet diversity score (DDS). Mann–Whitney U test was used to assess differences in risk of inadequacy across gender. Spearman’s rank correlation assessed associations between energy contributed by ultra-processed food and risk of nutrient inadequacy. Participants: A total of 589 adults (20–40 years) belonging to upper-middle and high-income groups. Results: The average individual DDS was 4·4 ± 0·6. Most of the participants (>80 %) had intakes less than national recommendations of pulses/eggs/flesh foods, milk/milk products, fruits, vegetables and nuts. Ultra-processed foods contributed to 17 % of total energy intake, 12 % of protein, 17 % of carbohydrate, 29 % of added sugar, 20 % of total fat and 33 % of Na intake. The average risk of nutrient inadequacies for Zn (98 % v. 75 %), folate (67 % v. 22 %) and niacin (83 % v. 44 %) was higher among males than females (P < 0·001). The average risk of nutrient inadequacies for Fe (58 % v. 7 %), vitamin B6 (95 % v. 90 %) and vitamin A (68 % v. 44 %) was higher among females than males (P < 0·001). There was a positive correlation between energy contributed by ultra-processed food and risk of niacin (ρ = 0·136, P = 0·001) and folate (ρ = 0·089, P = 0·049) inadequacy. Conclusion: Reformulating ultra-processed food to reduce fat, sugar and salt and increase micronutrients and behaviour change communication strategies that promote dietary diversity will improve micronutrient adequacy and diet quality.

Verónica Cabanas-Sánchez, Irene Esteban-Cornejo, Esther García-Esquinas et al.

Abstract Background Most studies on the effects of sleep, sedentary behavior (SB), and physical activity (PA) on mental health did not account for the intrinsically compositional nature of the time spent in several behaviors. Thus, we examined the cross-sectional and prospective associations of device-measured compositional time in sleep, SB, light PA (LPA) and moderate-to-vigorous PA (MVPA) with depression symptoms, loneliness, happiness, and global mental health in older people (≥ 65 years). Methods Data were taken from the Seniors-ENRICA-2 study, with assessments in 2015–2017 (wave 0) and 2018–2019 (wave 1). Time spent in sleep, SB, LPA and MVPA was assessed by wrist-worn accelerometers. Depression symptoms, loneliness, happiness, and global mental health were self-reported using validated questionnaires. Analyses were performed using a compositional data analysis (CoDA) paradigm and adjusted for potential confounders. Results In cross-sectional analyses at wave 0 (n = 2489), time-use composition as a whole was associated with depression and happiness (all p < 0.01). The time spent in MVPA relative to other behaviors was beneficially associated with depression (γ = -0.397, p < 0.001), loneliness (γ = -0.124, p = 0.017) and happiness (γ = 0.243, p < 0.001). Hypothetically, replacing 30-min of Sleep, SB or LPA with MVPA was beneficially cross-sectionally related with depression (effect size [ES] ranged -0.326 to -0.246), loneliness (ES ranged -0.118 to -0.073), and happiness (ES ranged 0.152 to 0.172). In prospective analyses (n = 1679), MVPA relative to other behaviors at baseline, was associated with favorable changes in global mental health (γ = 0.892, p = 0.049). We observed a beneficial prospective effect on global mental health when 30-min of sleep (ES = 0.521), SB (ES = 0.479) or LPA (ES = 0.755) were theoretically replaced for MVPA. Conclusions MVPA was cross-sectionally related with reduced depression symptoms and loneliness and elevated level of happiness, and prospectively related with enhanced global mental health. Compositional isotemporal analyses showed that hypothetically replacing sleep, SB or LPA with MVPA could result in modest but significantly improvements on mental health indicators. Our findings add evidence to the emerging body of research on 24-h time-use and health using CoDA and suggest an integrated role of daily behaviors on mental health in older people.

Gesmar Rodrigues Silva Segundo

Robert P. Nelson, Javier Chinen

Sofie van Rongen, Maartje P. Poelman, Lukar Thornton et al.

Abstract Background The association between the residential fast food environment and diet has gained growing attention. However, why the food environment affects food consumption is under-examined. This study aimed to investigate neighbourhood social norms with respect to fast food consumption as a potential mediating pathway between residential fast food outlet exposure and residents’ fast food consumption. Methods A correlational study was conducted in which a nationwide sample of 1038 respondents living across The Netherlands completed a survey. Respondents reported their fast food consumption (amount/week) as well as perceived descriptive and injunctive norms regarding fast food consumption in their neighbourhood. Fast food outlet exposure was measured by the average count of fast food outlets within a 400 m walking distance buffer around the zip-codes of the respondents, using a retail outlet database. Regression models were used to assess associations between residential fast food outlet exposure, fast food consumption, and social norm perceptions, and a bootstrapping procedure was used to test the indirect -mediation- effect. Separate analyses were performed for descriptive norms and injunctive norms. Results There was no overall or direct association between residential fast food outlet exposure and residents’ fast food consumption. However, fast food outlet exposure was positively associated with neighbourhood social norms (descriptive and injunctive) regarding fast food consumption, which in turn were positively associated with the odds of consuming fast food. Moreover, results of the bootstrapped analysis provided evidence of indirect effects of fast food outlet exposure on fast food consumption, via descriptive norms and injunctive norms. Conclusions In neighbourhoods with more fast food outlets, residents were more likely to perceive fast food consumption in the neighbourhood as more common and appropriate. In turn, stronger neighbourhood social norms were associated with higher fast food consumption. Acknowledging the correlational design, this study is the first that implies that neighbourhood social norms may be a mediating pathway in the relation between the residential fast food environment and fast food consumption. Future research may examine the role of neighbourhood social norms in other contexts and explore how the changing food environment may shift our consumption norms.

Seyed Mostafa Arabi, Golnaz Ranjbar, Leila Sadat Bahrami et al.

Abstract Aims The purpose of this review was to investigate the effect of vitamin D supplements on hemoglobin concentration in subjects aged 17.5–68 years old; using randomized controlled trials (RCTs). Methods Relevant RCT studies were identified from January 2000 to January 2019 by using MeSH terms in PubMed, Embase, Cochrane Library, Clinical trials, Scopus databases and gray literature. The studies were reviewed systematically, and quality assessments were evaluated by the guidelines of the Cochrane risk of bias. The effect of vitamin D supplements (n = 14) on hemoglobin concentration was considered as primary outcome, while its effects on the levels of ferritin, transferrin saturation and iron status were derived as secondary outcomes. In total, 1385 subjects with age range of 17.5 to 68 years old were examined for 3 h to 6 months; Mean (standard deviation) or median interquartile changes in the hemoglobin concentration in each treatment group was recorded for meta-analysis. Results Fourteen RCTs met the inclusion criteria. Current study findings propose that vitamin D supplementation leads to a non-significant reduction in hemoglobin levels in subjects (17.5–68 years old) [std. mean difference (SMD): 0.01; 95% CI: − 0.28, 0.29; P = 0.95], also it has no significant effect on ferritin concentrations [std. mean difference (SMD): -0.01; 95% CI: [− 0.20, 0.18; P = 0.91]. However, vitamin D supplementation demonstrated positive effects on transferrin saturation [mean difference (MD): 1.54; 95% CI: 0.31, 2.76; P = 0.01] and iron status [std. mean difference (SMD): 0.24; 95% CI: − 0.09, 0.39; P = 0.002]. Conclusion Current review concluded that supplementation with vitamin D had no significant effect on hemoglobin and ferritin levels while positive effects on transferrin saturation and iron status were observed. Further clinical studies are required to determine the actual effect of this intervention on hemoglobin levels.

Gunnar Sturfelt, Lennart Truedsson