Causal relationship between circulating vitamin C and 25-hydroxyvitamin D concentrations and common mental disorders-a Mendelian randomization study

Mental disorders seriously affect people’s health and social stability.This Mendelian randomization(MR)study was designed to investigate the causal relationship between circulating vitamin C(VC)or 25-hydroxyvitamin D(25(OH)D)levels and mental disorders.The data used for the MR analysis were derived from the summary genome-wide association studies(GWAS)database for VC and 25(OH)D and from the Finn Gen consortium for fourteen mental disorders.Based on the inverse variance weighted(IVW)method,we found a potential causal association between circulating VC and anxiety disorders(IVW:OR=1.139,95%CI:1.023-1.269,P=0.018).However,no causal association was found between VC or 25(OH)D and other mental disorders(P>0.05).In the reverse MR analysis,individuals with Alzheimer’s disease was causally associated with higher concentrations of circulating VC(P=0.012),while individuals with anxiety disorders had a negative association between the concentrations of 25(OH)D(P=0.012).However,the current evidence does not support a causal relationship between VC or 25(OH)D and other mental disorders.In addition,there was no causal association between circulating VC and 25(OH)D(P>0.05).Future studies are needed to confirm these findings and to elucidate the mechanisms of potential causality.

Vitamin D,selenium,and antidiabetic drugs in the treatment of type 2 diabetes mellitus with Hashimoto's thyroiditis

BACKGROUND Diabetes and thyroiditis are closely related.They occur in combination and cause significant damage to the body.There is no clear treatment for type-2 diabetes mellitus(T2DM)with Hashimoto's thyroiditis(HT).While single symptomatic drug treatment of the two diseases is less effective,combined drug treatment may improve efficacy.AIM To investigate the effect of a combination of vitamin D,selenium,and hypoglycemic agents in T2DM with HT.METHODS This retrospective study included 150 patients with T2DM and HT treated at The Central Hospital of Shaoyang from March 2020 to February 2023.Fifty patients were assigned to the control group,test group A,and test group B according to different treatment methods.The control group received low-iodine diet guidance and hypoglycemic drug treatment.Test group A received the control treatment plus vitamin D treatment.Test group B received the group A treatment plus selenium.Blood levels of markers of thyroid function[free T3(FT3),thyroid stimulating hormone(TSH),free T4(FT4)],autoantibodies[thyroid peroxidase antibody(TPOAB)and thyroid globulin antibody(TGAB)],blood lipid index[low-density lipoprotein cholesterol(LDL-C),total cholesterol(TC),triacylglycerol(TG)],blood glucose index[fasting blood glucose(FBG),and hemoglobin A1c(HbA1c)]were measured pre-treatment and 3 and 6 months after treatment.The relationships between serum 25-hydroxyvitamin D3[25(OH)D3]level and each of these indices were analyzed.RESULTS The levels of 25(OH)D3,FT3,FT4,and LDL-C increased in the order of the control group,test group A,and test group B(all P<0.05).The TPOAB,TGAB,TC,TG,FBG,HbA1c,and TSH levels increased in the order of test groups B,A,and the control group(all P<0.05).All the above indices were compared after 3 and 6 months of treatment.Pre-treatment,there was no divergence in serum 25(OH)D3 level,thyroid function-related indexes,autoantibodies level,blood glucose,and blood lipid index between the control group,test groups A and B(all P>0.05).The 25(OH)D3 levels in test groups A and B were negatively correlated with FT4 and TGAB(all P<0.05).CONCLUSION The combination drug treatment for T2DM with HT significantly improved thyroid function,autoantibody,and blood glucose and lipid levels.

Unlocking the potential-vitamin D in prostate cancer prevention

Prostate cancer poses a significant health challenge globally,demanding proactive prevention strategies.This editorial explores the emerging role of vitamin D in prostate cancer prevention.While traditionally associated with bone health,vitamin D is increasingly recognized for its broader impact on immune function,cellular signaling,and cancer prevention.Epidemiological studies suggest an intriguing link between vitamin D deficiency and elevated prostate cancer risk,particularly in regions with limited sunlight exposure.Mechanistically,vitamin D regulates cellular processes,inhibiting unchecked cancer cell growth and bols-tering immune surveillance.Personalized prevention strategies,considering individual factors,are deemed essential for harnessing the full potential of vitamin D.To unlock this potential,the future calls for robust research,public awareness campaigns,dietary improvements,and vigilant medical guidance.Collaborative efforts are poised to pave the way toward a future where vitamin D stands as a sentinel in prostate cancer prevention,ushering in hope and improved health for men worldwide.

Association of Serum Folate and Vitamin B_(12) Concentrations with Obesity in Chinese Children and Adolescents

Objective This study aimed to evaluate the associations of serum folate and/or vitamin B12 concentrations with obesity among Chinese children and adolescents.Methods A cross-sectional study was conducted including 3,079 Chinese children and adolescents,aged 6 to 17 years,from Jiangsu,China.Anthropometric indices,such as,children's body mass index(BMI),BMI z-scores,waist circumference,and waist-to-height ratio were utilized.Multivariable linear regression and generalized additive models were used to investigate the associations of serum folate and vitamin B12 levels with anthropometric indices and odds of obesity.Results We observed that serum vitamin B12 concentrations were inversely associated with all anthropometric indices and the odds of general obesity[odds ratio(OR)=0.68;95%confidence interval(CI)=0.59,0.78]and abdominal obesity(OR=0.68;95%CI=0.60,0.77).When compared to participants with both serum vitamin levels in the two middle quartiles,those with both serum folate and vitamin B12 levels in the highest quartile were less prone to general(OR=0.31,95%CI=0.19,0.50)or abdominal obesity(OR=0.46,95%CI=0.31,0.67).Conversely,participants with vitamin B12 levels in the lowest quartile alongside folate levels in the highest quartile had higher odds of abdominal obesity(OR=2.06,95%CI=1.09,3.91).Conclusion Higher serum vitamin B12 concentrations,but not serum folate concentrations,were associated with lower odds of childhood obesity.Children and adolescents with high levels of vitamin B12 and folate were less likely to be obese.

Selenium,Type-2 Diabetes,and the Possible Protective Role of Vitamin D

Diabetes is a pervasive and serious global health issue.According to the International Diabetes Federation report,463 million adults worldwide were living with diabetes in 2019,and this number is projected to reach 700 million in 2045^([1]).

Association of plasma vitamin A level with type 2 diabetes mellitus:a community aging population-based cross-sectional study

Recent studies indicated that vitamin A(VA)might be involved in the pathology of type 2 diabetes mellitus(T2DM).This cross-sectional study was conducted to explore the association between circulating VA level and T2DM.A total of 1818 subjects aged 50 years old and above were recruited from the community.Binomial logistic regression and restricted cubic spline(RCS)were applied to analyze the association of plasma VA level with the risk of T2DM.Serum VA and lipid-adjusted VA levels of T2DM patients were significantly higher than that of non-T2DM subjects(P<0.05).The ratios of plasma VA/total cholesterol(TC),VA/high-density lipoprotein cholesterol(HDL-c)and VA/low-density lipoprotein cholesterol(LDL-c)were positively associated with the risk of T2DM in the aging population(P<0.05).Compared with the Q1 level,subjects with Q2 to Q3 levels of plasma VA/triglyceride(TG)have decreased risk of T2DM(odds ratio(OR)Q2=0.68,P_(Q2)=0.021;ORQ3=0.59,P_(Q3)<0.01).Our results indicated that the imbalance of circulating lipids and VA might affect the relationship between VA and T2DM.The middle and aging subjects with higher ratios of plasma VA/TC,VA/HDL-c,and VA/LDL-c displayed increased risk for T2DM,but the moderate ratio of VA/TG might protect against risk of T2DM.

Vitamin A regulates mitochondrial biogenesis and function through p38 MAPK‑PGC‑1α signaling pathway and alters the muscle fiber composition of sheep

Background Vitamin A(VA)and its metabolite,retinoic acid(RA),are of great interest for their wide range of physiological functions.However,the regulatory contribution of VA to mitochondrial and muscle fiber composition in sheep has not been reported.Method Lambs were injected with 0(control)or 7,500 IU VA palmitate into the biceps femoris muscle on d 2 after birth.At the age of 3 and 32 weeks,longissimus dorsi(LD)muscle samples were obtained to explore the effect of VA on myofiber type composition.In vitro,we investigated the effects of RA on myofiber type composition and intrinsic mechanisms.Results The proportion of type I myofiber was greatly increased in VA-treated sheep in LD muscle at harvest.VA greatly promoted mitochondrial biogenesis and function in LD muscle of sheep.Further exploration revealed that VA elevated PGC-1αmRNA and protein contents,and enhanced the level of p38 MAPK phosphorylation in LD muscle of sheep.In addition,the number of type I myofibers with RA treatment was significantly increased,and type IIx myofibers was significantly decreased in primary myoblasts.Consistent with in vivo experiment,RA significantly improved mitochondrial biogenesis and function in primary myoblasts of sheep.We then used si-PGC-1αto inhibit PGC-1αexpression and found that si-PGC-1αsignificantly abrogated RA-induced the formation of type I myofibers,mitochondrial biogenesis,MitoTracker staining intensity,UQCRC1 and ATP5A1 expression,SDH activity,and enhanced the level of type IIx muscle fibers.These data suggested that RA improved mitochondrial biogenesis and function by promoting PGC-1αexpression,and increased type I myofibers.In order to prove that the effect of RA on the level of PGC-1αis caused by p38 MAPK signaling,we inhibited the p38 MAPK signaling using a p38 MAPK inhibitor,which significantly reduced RA-induced PGC-1αand MyHC I levels.Conclusion VA promoted PGC-1αexpression through the p38 MAPK signaling pathway,improved mitochondrial biogenesis,and altered the composition of muscle fiber type.

The efficacy of vitamin E in preventing arthrofibrosis after joint replacement

Background:Arthrofibrosis is a joint disorder characterized by excessive scar formation in the joint tissues.Vitamin E is an antioxidant with potential anti-fibroblastic effect.The aim of this study was to establish an arthrofibrosis rat model after joint replacement and assess the effects of vitamin E supplementation on joint fibrosis.Methods:We simulated knee replacement in 16 male Sprague–Dawley rats.We immobilized the surgical leg with a suture in full flexion.The control groups were killed at 2 and 12 weeks(n=5 per group),and the test group was supplemented daily with vitamin E(0.2 mg/mL)in their drinking water for 12 weeks(n=6).We performed histological staining to investigate the presence and severity of arthrofibrosis.Immunofluorescent staining andα2-macroglobulin(α2M)enzyme-linked immunosorbent assay(ELISA)were used to assess local and systemic inflammation.Static weight bearing(total internal reflection)and range of motion(ROM)were collected for functional assessment.Results:The ROM and weight-bearing symmetry decreased after the procedure and recovered slowly with still significant deficit at the end of the study for both groups.Histological analysis confirmed fibrosis in both lateral and posterior periarticular tissue.Vitamin E supplementation showed a moderate anti-inflammatory effect on the local and systemic levels.The vitamin E group exhibited significant improvement in ROM and weight-bearing symmetry at day 84 compared to the control group.Conclusions:This model is viable for simulating arthrofibrosis after joint replacement.Vitamin E may benefit postsurgical arthrofibrosis,and further studies are needed for dosing requirements.

Unraveling colorectal cancer prevention:The vitamin D-gut flora-immune system nexus

Colorectal cancer(CRC)is one of the most common cancers diagnosed in the world.Although environmental and genetic factors play a major role in the pathogenesis of CRC,extensive research has suggested that vitamin D may play a pivotal role in the development of CRC.Vitamin D,primarily obtained through sunlight exposure,dietary sources,and supplements,has long been recognized for its essential functions in maintaining health,including immune regulation.This article delves into the intricate relationship between vitamin D,the immune system,gut flora,and the prevention of CRC.It presents a synthesis of epidemiological data,experimental studies,and clinical trials,highlighting the mechanisms by which vitamin D influences immune cell function,cytokine production,and inflammation.By enhancing the immune system’s surveillance and antitumor activity,vitamin D may offer a promising avenue for CRC prevention.Furthermore,this comprehensive review delves into the prospective clinical applications of vitamin D supplementation and delineates the forthcoming avenues of research in this dynamic domain.Additionally,the paper tentatively outlines a spectrum of prophylactic impacts of vitamin D on CRC,emphasizing its significant potential in reducing CRC risk through shedding light on its mechanisms,encompassing antineoplastic mechanisms,influences on the immune system,and modulation of the gut microbiome.

Effects of vitamin family members on insulin resistance and diabetes complications

The following letter to the editor highlights the article“Effects of vitamin D supplementation on glucose and lipid metabolism in patients with type 2 diabetes mellitus and risk factors for insulin resistance”in World J Diabetes 2023 Oct 15;14(10):1514-1523.It is necessary to explore the role of vitamin family members in insulin resistance and diabetes complications.

Hemolysis attributed to high dose vitamin C:Two case reports

BACKGROUND High-dose vitamin C treatment(HVCT)can reduce the adverse effect of chemotherapy and enhance the effect of antitumor therapy,which has been considered one of the safest alternative treatments.However,the severity of its adverse effects may have been underestimated.The most serious adverse effect is hemolysis,which may result in acute kidney injury or death.Although glucose-6-phosphate dehydrogenase(G6PD)deficiency is considered to be the main cause,the probability and pathological mechanism are not completely understood,leading to a lack of effective and standardized treatment methods.CASE SUMMARY Two patients with colorectal cancer developed hemolytic anemia after using 1 g/kg HVCT.In contrast to previous cases,the lowest hemoglobin level in the two cases was<50 g/L,which was lower than previously reported.This may be because Case 1 had chronic hepatitis B for many years,which caused abnormal liver reserve function,and Case 2 had grade II bone marrow suppression.Both patients improved and were discharged after blood replacement therapy.Our cases had the most severe degree of hemolysis but the best prognosis,suggesting that our treatment may be helpful for rescue of drug-induced hemolysis.This is the first review of the literature on hemolysis caused by HVCT,and we found that all patients with G6PD deficiency developed hemolysis after HVCT.CONCLUSION G6PD deficiency should be considered as a contraindication to HVCT,and it is not recommended for patients with bone marrow suppression,moderate-tosevere anemia,hematopoietic abnormalities,or abnormal liver and kidney function.Early blood purification and steroid therapy may avoid acute kidney injury or death caused by HVCT-related hemolytic anemia.

Vitamin D, Parathyroid Hormone, Insulin Sensitivity and Islet β-Cell Secretory Function in Diabetic Patients from South Kivu in the Democratic Republic of Congo: Cross-Sectional Study

Background: The role of vitamin D and parathyroid hormone in the metabolic profile of type 2 diabetes mellitus in sub-Saharan Africa has not been adequately assessed. The aim of this study was to determine the prevalence of low vitamin D level and secondary hyperparathyroidism and their association with insulin sensitivity and β-cell secretory function among Congolese type 2 diabetics. Methodology: Fasting glycaemia, fasting insulin, 25OH D3 and human parathyroid hormone (hPTH) were measured in one hundred and eighty-four type 2 diabetic patients followed as outpatients in South Kivu. Levels of 25OH D3 65 pg/ml defined low vitamin D and elevated parathyroid hormone levels, respectively. The HOMA model was used to measure insulin sensitivity and β-cell secretory function. Results: Medians (IQR) were 25.3 (20.4 - 32.4) ng/ml for 25OH D3 and 53.7 (38.4 - 115.7) pg/ml for hPTH. 58.7% of diabetics had insulin resistance, 126 (68.5%) had low vitamin D and 80 (43.5%) had hyperparathyroidism. In multivariate analysis, hPTH (partial r = −0.28;p = 0.0002) and 25OH D3 (partial r = 0.16;p = 0.03) showed an independent association with insulin sensitivity after adjustment for body mass index and waist circumference. Finally, hPTH (partial r = 0.27;p = 0.0002) was the sole determinant of β-cell secretory function. Conclusions: This study confirms the high prevalence of low vitamin D level and secondary hyperparathyroidism and their association with insulin resistance and impaired islet β-cell secretory function among Congolese with type 2 diabetes mellitus. Vitamin D and calcium supplementation should be envisaged for cases of deficiency in this region.

Vitamin D and selenium for type 2 diabetes mellitus with Hashimoto’s thyroiditis:Dosage and duration insights

This letter discusses the publication by Feng et al.Iodine,selenium,and vitamin D are closely associated with thyroid hormone production in humans;however,the efficacy of selenium and vitamin D supplementation for type 2 diabetes mellitus(T2DM)patients with Hashimoto’s thyroiditis(HT)remains controversial.In the retrospective study we discuss herein,the authors highlighted significant improvements in thyroid function,thyroid antibodies,blood glucose,and blood lipid in T2DM patients with HT following addition of vitamin D and selenium to their antidiabetic regimens,underscoring the value of these supplements.Our team is currently engaged in research exploring the relationship between micronutrients and HT,and we have obtained invaluable insights from the aforementioned study.Based on this research and current literature,we recommend a regimen of 4000 IU/day of vitamin D and 100-200μg/day of selenium for over three months to six months for patients with HT,particularly for those with concurrent T2DM.

Assessment of Oral Anticoagulation with Vitamin K Antagonists in Patients Living in a Low-Income Country of West Africa

Introduction: Despite the rise of direct oral anticoagulants (DOACs), vitamin K antagonists (VKA) remain the most widely used oral anticoagulants in developing countries. The aim of this study was to estimate the prevalence of good anticoagulation in patients treated with VKA in Lomé and describe associated factors. Methods: This was a cross-sectional study conducted from November 2019 to October 2020 in the cardiology departments of two University teaching hospitals in Lomé (CHU Sylvanus Olympio and CHU Campus), involving patients on VKA for ≥3 months, with a target international normalized ratio (INR) of 2.5 and a therapeutic margin between 2 and 3. The quality of anticoagulation was assessed by the time in therapeutic range (TTR) which was assessed by the Rosendaal method. Good anticoagulation was defined by a TTR > 70%. Results: A total of 344 patients were included (mean age = 58 ± 13.8 years, women = 56.1%). Indications for VKA treatment were represented by venous thromboembolic disease (43.3%), supraventricular arrhythmia (28.2%), severe left ventricular systolic dysfunction (19.8%) and pulmonary hypertension (8.7%). The average TTR was 47.6 ± 20.8%. The rate of good anticoagulation was 17.7%. Factors associated with good anticoagulation were the use of fluindione vs acenocoumarol (OR = 11.17;95% CI: 3.2 - 39.6;p = 0.0002), concomitant low-dose aspirin (OR 4.44;95% CI: 1.4 - 13.9;p = 0.01) and INR monitoring exclusively by the patient himself (OR = 4.92;95% CI: 1.5 - 16.3;p = 0.008). The rate of thromboembolic and hemorrhagic complications was each 2.6% and was not correlated with the quality of anticoagulation. Quality of anticoagulation by VKAs was poor in our practice. Factors associated with good anticoagulation were the use of fluindione vs acenocoumarol, concomitant low-dose aspirin and monitoring of INR exclusively by the patient himself. Conclusion: The quality of oral anticoagulation by VKAs could be improved in our practice by the creation of anticoagulation clinics for better therapeutic education of patients and efficient management of VKA dose, and the use of prescription assistance software.

Vitamin D, selenium in type 2 diabetes and Hashimoto's thyroiditis: Is it effective?

The study by Feng et al,explores treatment approaches for these coexisting conditions.It emphasizes the potential advantages of selenium and vitamin D supplementation but also raises methodological and patient selection concerns.Findings indicate a complex interplay between interventions and disease markers,prompting the need for further research.Despite limitations,the study offers valuable insights into managing the intricate relationship between type 2 diabetes mellitus and Hashimoto's thyroiditis.The authors'contributions shed light on potential treatment avenues,although careful consideration of study design and patient characteristics is warranted for future investigations in this domain.

Vitamin D and prostate cancer prevention

Vitamin D is a hot topic nowadays,especially its relationship with cancer pre-vention.Normally,vitamin D is associated with bone health principally,but the new research has discovered an impact on immune function and cellular sig-naling,even in same studies talk about a hormone,however,the most important relationship is its implication in cellular processes,inhibiting cancer growth.For now,the recent studies are oriented about a benefit and a cause-effect relationship between prostate cancer and normal levels of vitamin D.This premise opens a lot of questions in this scenario.This editorial highlighted the most important studies in this area.

Preparation and Characterization of Vitamin-D Incorporated Marshmallow

This project looks at a novel way to enhance the sensory experience of vitamin D ingestion by incorporating it into marshmallows. This investigation used a human panel taste test with twelve individuals, an index of swelling, and a stability evaluation. Samples of vitamin D infused marshmallows were prepared and given to participants in the human panel taste test, which evaluated mouthfeel and flavor. By analyzing dissolving behavior, the swelling index test revealed unexpected erosion. In addition, a temperature threshold for storage conditions was found through a temperature sensitivity test. All of these techniques assessed the feasibility and palatability of vitamin D supplementation with marshmallow flavor, offering insights into both the possible advantages and difficulties. The marshmallow infusion technique effectively covered up the disagreeable taste of vitamin D pills, leading to reviews that were overwhelmingly favorable (“Moderate Sweet”) and that indicated a pleasant mouthfeel. During the swelling index test, it showed erosion behavior, suggesting a certain kind of dissolution that is advantageous for nutritional absorption. Furthermore, the study discovered a temperature sensitivity threshold, highlighting how crucial proper storage conditions are.

Neurological Manifestations of Vitamin B12 Deficiency: About a Case

The authors report a case of deficient sensory neuropathy secondary to vitamin B12 deficiency, diagnosed in the neurology department of the Sino-Central African Friendship University Hospital in Bangui. The diagnosis was made possible by electroneuromyography which showed subclinical neurological damage associated with hematological damage (anemia). Through this observation, we recall the diagnostic criteria of the disease in a context of difficult medical practice. .

Carpel Tunnel Syndrome: A Link with Vitamin D, Body Mass Index and Hyperlipidemia

Introduction: Carbai tunnel syndrome [CTS] is compression of the median nerve at the wrist , this causes tingling in the hands, pain, numbness, tingling in the fingers particularly the thumb, index and middle fingers, loss of sensation in the hands and fingers, also weakness in the hands. The aim of the present study was to study a possible association which could be found between electrophysiological data in CTS, BMI, hyperlipidemia, and vitamin D [Vit D] levels. Methods: We used a sample of 40 females of the same age group, who were divided into Group 1 as a control consists of 18 healthy females and Group II consisted of 22 age matched females with clinical and electrophysiological evidence of CTS. We measured atherogenic index [AI] as a marker of hyperlipidemia, body mass index [BMI], Vit D status and electrophysiological tests of CTS. Results: Subjects with CTS had deficient Vit D status, they had significantly high atherogenic index (AI), and significant high BMI all compared to control Group I. Median sensory conduction velocity was significantly correlated negatively with BMI and atherogenic index, and positively correlated significantly with Vit D status. But median sensory and motor action potential latency were significantly correlated positively with BMI and atherogenic index, and negatively correlated significantly with Vit D status The analysis revealed BMI, atherogenic index and Vit D status as predictors of median nerve sensory and motor action potential latency and sensory nerve conduction velocity in CTS. Conclusion: The results of this study suggest that obesity and hyperlipidemia are potent CTS risk factors and declared the direct association between Vit D status and CTS occurrence. Our study supports the notion of the compensatory neuroprotective role of Vit D which could have a direct impact on the nerves integrity as it has an anti-inflammatory property which acts in relieving nervous insults and stress. .

Prevalence of vitamin D deficiency in exclusively breastfed infants at Charoenkrung Pracharak Hospital

BACKGROUND Vitamin D deficiency is a common problem in exclusively breastfed infants,with supplementation recommended by various international medical organizations.However,in Thailand,no advice for routine vitamin D supplementation is available.Thus,this study investigated the prevalence of vitamin D deficiency and its associated factors in exclusively breastfed infants in Bangkok,Thailand.AIM To investigated the prevalence of vitamin D deficiency and its associated factors in exclusively breastfed infants in Bangkok,Thailand.METHODS This descriptive observational cross-sectional study assessed 1094-month-old infants at Charoenkrung Pracharak Hospital from May 2020 to April 2021.The 25-OH vitamin D level of the infants was measured using an electrochemiluminescence binding assay.Vitamin D deficiency was defined as 25-OH level<20 ng/mL,with vitamin D insufficiency 20-30 ng/mL.The sun index and maternal vitamin D supplementation data were collected and analyzed using the independent t-test,univariate logistic regression,and multivariate logistic regression to identify the associated factors.RESULTS The prevalences of vitamin D deficiency and vitamin D insufficiency were 35.78%and 33.03%,respectively with mean serum 25-OH vitamin D levels in these two groups 14.37±3.36 and 24.44±3.29 ng/mL.Multivariate logistic regression showed that the main factors associated with vitamin D status were maternal vitamin D supplementation and birth weight,with crude odds ratios 0.26(0.08–0.82)and 0.08(0.01–0.45),respectively.The sun index showed no correlation with the 25-OH vitamin D level in exclusively breastfed infants(r=−0.002,P=0.984).CONCLUSION Two-thirds of healthy exclusively breastfed infants had hypovitaminosis D.Vitamin D supplementation prevented this condition and was recommended for both lactating women and their babies.