Vitamin B12 deficiency in African American and white octogenarians and centenarians in Georgia

Objective

Test the hypotheses that vitamin B12 deficiency would be prevalent in octogenarians and centenarians and associated with age, gender, race/ethnicity, living arrangements (community or skilled nursing facility), animal food intake, B-vitamin supplement use, atrophic gastritis, folate status, and hematological indicators.

Design

Population-based multi-ethnic sample of adults aged 80 to 89 and 98 and above.

Setting

Northern Georgia in the United States.

Participants

Men and women aged 80 to 89 (octogenarians, n = 80) and 98 and older (centenarians, n = 231).

Measurements

Wilcoxon signed-rank tests, Fisher℉s exact tests, and logistic regression analysis was used to examine the associations of vitamin B12 status with the variables of interest.

Results

After excluding participants receiving vitamin B12 injections (n = 17), the prevalence of vitamin B12 deficiency was higher in centenarians than in octogenarians (35.3% vs. 22.8%, p < 0.05, defined as plasma vitamin B12 < 258 pmol/L and serum methylmalonic acid > 271 nmol/L and methylmalonic acid > serum 2-methylcitrate) and in both age groups was correlated with significantly higher homocysteine (p < 0.05) and lower plasma and red cell folate (p < 0.01), but was not related to hemoglobin, anemia, mean cell volume, or macrocytosis. In logistic regression analysis, the probability of being vitamin B12-deficient was significantly increased by being a centenarian vs. octogenarian (p < 0.03), by being white vs. African American (p < 0.02), by increasing severity of atrophic gastritis (p < 0.001), and by not taking oral B-vitamin supplements (p < 0.01), but was not related to gender, living arrangements, or animal food intake.

Conclusions

Centenarians and octogenarians are at high risk for vitamin B12 deficiency for many of the same reasons identified in other older adult populations. Given the numerous potential adverse consequences of poor vitamin B12 status, efforts are needed to ensure vitamin B12 adequacy in these older adults.     

Vitamin D Deficiency and Insufficiency in the Georgia Older Americans Nutrition Program

ABSTRACT

Serum 25-hydroxyvitamin D (25(OH)D) status in older adults enrolled in community-based meal programs is not well characterized. The objective was to identify predictors of poor serum 25(OH)D status and the response to vitamin D supplementation in a convenience sample from the Older Americans Act Nutrition Program (OAANP) in northeast Georgia (N = 158, mean age = 77 years, 81% women, 69% Caucasian, 31% African American). Mean serum 25(OH)D was 55 nmol/l, and intakes of vitamin D and calcium from foods were very low. Vitamin D insufficiency (25(OH)D 25- < 50 nmol/l) occurred in 36.7%. Vitamin D deficiency occurred in 8.2% (25(OH)D < 25 nmol/l) and was associated with low milk intake, low sunlight exposure, receiving meals at home, tobacco use, depression, dementia, antianxiety medication, poor instrumental activities of daily living, and low calf circumference (p ≤ 0.05). When non-supplement users (n = 28) were given a multivitamin with vitamin D (10 µg/d) and calcium (450 mg/d) for 4 months, 25(OH)D increased from 50 to 78 nmol/l, the prevalence of poor vitamin D status (25(OH)D < 50 nmol/l) decreased from 61% to 14%, and serum alkaline phosphatase decreased by 10% (p < 0.01). High body weight appeared to attenuate the increase in 25(OH)D in response to the multivitamin supplement (p ≤ 0.05). In conclusion, OAANP services did not prevent poor vitamin D and calcium status, but a supplement with vitamin D and calcium was beneficial.     

Vitamin D deficiency in patients receiving home parenteral nutrition

Background: In addition to its role in bone metabolism, vitamin D has important immunomodulatory and antineoplastic effects. Patients on home parenteral nutrition (HPN) receive most of their vitamin D from intravenous (IV) supplementation. Vitamin D deficiency is common in the general population, and the adequacy of vitamin D supplementation in HPN patients is unclear. The purpose of this study is to determine the vitamin D status of patients on HPN. Methods: Consecutive patients seen in a regional home nutrition program had their oral and IV vitamin D intakes determined. Plasma 25‐hydroxyvitamin D levels were measured in all patients. Intake of calcium, magnesium, and phosphate were also determined. Results: The mean 25‐hydroxyvitamin D level in 22 patients receiving HPN for a mean of 33.5 months (range, 1–177) was 42 nmol/L. Vitamin D deficiency was present in 15 (68%) patients and vitamin D insufficiency in 6 (27%) patients. The mean dietary vitamin D intake was 79.5 IU per day, while the mean IV supplementation was 166 IU per day. Conclusions: In this study of a regional Canadian HPN program, there was a high prevalence of vitamin D deficiency/insufficiency affecting virtually all patients. All patients receiving HPN should be supplemented with vitamin D and have their 25‐hydroxyvitamin D levels monitored. Further studies are required to determine optimal methods and dosing of vitamin D replacement using oral supplements or ultraviolet light therapy.     

Vitamin D Insufficiency Among Postmenopausal Women in Urban and Rural Areas in Guilan,Northern Iran

This study aimed to describe vitamin D status in postmenopausal women in urban and rural areas in Guilan, northern Iran. Between October 2004 and February 2005 a group of 750 women older than 50 years was randomly selected from urban and rural areas in Guilan. The participants were interviewed to collect data on age, educational level, body weight, height, employment status, reproductive history, medications, history of illness, and supplement use. Serum 25(OH) D was measured in 646 women (427 in urban areas and 219 women in rural areas). Serum 25(OH) D levels in urban and rural postmenopausal women were 18.5 ± 13.5 ng/ml and 22.9 ± 13.8 ng/ml (P < 0.0001), respectively. In urban and rural areas, 84.7% and 79.5% of the women had serum 25(OH) D levels less than 30 ng/ml, respectively. In this study, serum vitamin D levels and prevalence of vitamin D insufficiency was related to educational level in urban women. The urban women in the lowest educational level (<5 years schooling) had a better vitamin D status than other educational groups. This study showed that a high proportion of postmenopausal women living in Guilan province had vitamin D insufficiency. Vitamin D inadequacy was more common in urban areas and especially in the upper social class. Supplement use and national strategies to prevent vitamin D insufficiency are strongly needed in this community.     

Vitamin D status among older community dwelling men living in a sunny country and associations with lifestyle factors: The concord health and ageing in men project, Sydney, Australia

Objectives

Inadequate vitamin D status (25-hydroxyvitamin D (25(OH)D) concentrations <50 nmol/L) is an increasingly important public health issue in Australia. The aim of this analysis is to describe 25(OH)D levels in community dwelling men aged ≥70 years in Sydney, Australia, and to determine associations between serum 25(OH)D levels and socioeconomic and lifestyle factors.

Design

A population-based, crosssectional analysis of the baseline phase of the Concord Health and Ageing in Men Project (CHAMP), a large epidemiological study conducted in Sydney between January 2005 and May 2007.

Participants

1659 noninstitutionalised men aged ≥70 years.

Methods

The cross-sectional analysis of the baseline phase of the Concord Health and Ageing in Men Project (CHAMP), a large epidemiological study conducted in Sydney between January 2005 and May 2007. Participants included 1659 community dwelling men who were interviewed and had clinical assessments. Main outcome measurements included serum 25(OH)D levels measured in blood samples using a radioimmunoassay kit (DiaSorin Inc., Stillwater, MN). Covariates included age, socioeconomic measures, season of blood sample, physical activity, sun exposure, vitamin D supplement use, cigarette smoking status, alcohol consumption, obesity and measures of health.

Results

Prevalence of vitamin D insufficiency was 43.0%; highest in winter (55.5%) and spring (53.9%), and was associated with season (winter and spring), low physical activity, avoidance of sun exposure, current smoking and obesity, even after adjustment for confounding factors.

Conclusion

Inadequate vitamin D status is highly prevalent among Australian older men and is associated with specific lifestyle factors. These findings emphasize the need to screen and monitor 25(OH)D levels in this population group, despite living in a sunny country such as Australia.     

Body Size and Serum 25 Hydroxy Vitamin D Response to Oral Supplements in Healthy Older Adults

Background: Vitamin D insufficiency is prevalent in the northeast United States. Since vitamin D insufficiency is readily amenable to supplementation, it is important to understand what factors are associated with serum 25 hydroxy vitamin D (25(OH)D) response to vitamin D supplementation.

Objective: In this study we examined the association of serum 25(OH)D response to vitamin D supplementation with body size in a population of elderly subjects.

Methods: 257 healthy, ambulatory men and women 65 years of age or older were randomly assigned to treatment with either 700 IU/day (17.5 μg/d) of supplemental vitamin D₃ and 500 mg/day (12.5 mmol/d) of supplemental calcium, or to placebo.

Results: In multivariate regression analyses, after adjusting for baseline 25(OH)D, season, and sex, we found change in 25(OH)D to be inversely associated with baseline BMI (p = 0.01) in subjects treated with supplements for one year. Change in 25(OH)D was also negatively associated with other baseline anthropometric measurements in these subjects.

Conclusion: Our study implies that body size should be taken into account when estimating the amount of vitamin D intake needed to raise 25(OH)D to the desired level.     

Evaluation of the deficiency status of 25-hydroxyvitamin D and associated factors in Southwest China: A hospital-based retrospective cross-sectional analysis of a low-latitude,high-altitude,multiracial region

Vitamin D deficiency is widespread in different populations and regions worldwide and has become a global health issue. The vitamin D status of the population in the Yunnan Province of Southwest China has not been evaluated to date. Therefore, in this study, we evaluated the vitamin D status according to the serum concentrations of 25-hydroxyvitamin D (25(OH)D) in individuals of Yunnan Province, a low-latitude, high-altitude and multiracial region in China. The data on 25(OH)D concentrations from October 2012 to December 2017 were retrospectively collected and assessed using the laboratory information system from 52 950 hospital-based participants (age, 1 day–96 years; females, 73.74%). The serum concentration of 25(OH)D was evaluated using a chemiluminescent immunoassay. The analysis was stratified by sex, age, sampling season, testing year, minority, residential district, latitude, altitude and meteorological factors. Vitamin D status was classified as follows: severe deficiency: <10 ng/mL; deficiency: <20 ng/mL; insufficiency: <30 ng/mL; and sufficiency: ≥30 ng/mL. The results showed that vitamin D deficiency is highly prevalent in Yunnan Province in a hospital-based cohort, with a deficiency and severe deficiency rate of 65.1% and a sufficiency rate of 5.30%. Significantly lower vitamin D levels and sufficiency rates were observed in females than in males (20.13 ± 7.22 ng/mL vs. 17.56 ± 6.66 ng/mL and 8.20% vs. 4.20%; p < 0.01, respectively); in spring and winter (16.93 ± 6.24 ng/mL; 2.97% and 16.38 ± 6.43 ng/mL; 3.06%, respectively) than in summer and autumn (20.23 ± 7.14 ng/mL; 8.02% and 19.10 ± 6.97 ng/mL; 6.61% [p < 0.01], respectively); and in older individuals (0–6 years: 28.29 ± 13.13 ng/mL vs. >60 years: 14.88 ± 8.39 ng/mL; p < 0.01). Relatively higher vitamin D levels were observed in individuals of Yi, Zhuang, Hani, Dai, Miao and Lisu minorities and lower levels in individuals of Hui and Zang minorities compared with those of the Han nationality (p < 0.01). The mean sunlight duration, mean air temperature, maximum ultraviolet value and latitude were significantly correlated with vitamin D levels (r = −0.53, 0.60, 0.31, −0.68, respectively; p < 0.05). These results suggest that vitamin D status is influenced by sex, age, minority, latitude and some meteorological factors in areas with high and low altitudes. Hence, new public health policies, such as advice on sunshine exposure, food fortification and nutrition education, as well as the implementation of vitamin D supplementation programmes must be considered to alleviate vitamin D deficiency in Yunnan province, Southwest China.     

Vitamin D status in a rural postmenopausal female population

BACKGROUND: Inadequate vitamin D nutritional status is increasingly recognized as common in North American and European populations, but the extent of the shortfall and the parameters of the distribution for populations of interest remain uncertain. PURPOSE: To report the distribution of values for serum 25-hydroxyvitamin D [25(OH)D] in a population of rural postmenopausal women, together with quantification of factors related to vitamin D status. SETTING: Nine largely agrarian counties in eastern Nebraska (approximately 41 degrees N). PARTICIPANTS: A population-based sample of 1,179 women 55 years of age and older recruited into a four-year trial of calcium and vitamin D supplementation. METHODS: Baseline biochemical, dietary, and anthropometric measurements obtained on entry into trial. RESULTS: Serum 25(OH)D concentration at baseline varied cyclically with season, with the solar cycle explaining 2.9% of the total variance (P < 0.001). Mean seasonally adjusted 25(OH)D concentration was 71.1 nmol/L. Serum 25(OH)D also exhibited the expected inverse curvilinear relationship with serum parathyroid hormone (PTH), with the inflection point of the curve located at approximately 80 nmol/L. Supplements containing vitamin D were regularly taken by 59% of the cohort (median dose: 200 IU/d). Nevertheless, approximately 4% of all women had values below the laboratory reference range and more than two-thirds fell below 80 nmol/L. Seasonally adjusted serum 25(OH)D concentration was positively correlated with the size of daily vitamin D supplement dose, and negatively with age, weight, and body mass index (P < 0.01 for all). In stepwise multiple linear regression models, weight, age, and supplement dose were independently correlated with seasonally adjusted serum 25(OH)D, and together explained 19% of the total variance of adjusted 25(OH)D concentration. Women taking supplements had only one-sixth the chance of having a 25(OH)D value below the reference limit of the assay, compared to women who did not use supplements. CONCLUSIONS: Approximately two-thirds of this rural population fell below 80 nmol/L, a value considered to be the lower end of the optimal range. Based on the slope of 25(OH)D on supplement dose observed in these women, it would require an additional vitamin D input of nearly 2000 IU/d to reach the goal of an RDA for vitamin D, i.e., to bring 97.5% of the cohort to levels of 80 nmol/L or higher.     

Calcium and vitamin D use among older adults in U.S.: Results from national survey

Objective

This study was conducted to describe a 10-year trend of the supplement from 2000 to 2009 and to evaluate age, gender and racial disparities using a national level health data.

Design

Cross-sectional observational study.

Setting and Participants

Data collected from patient visit records to stand-alone US ambulatory care clinics. Visits made by men and women who were 40 years of age and older were included (n=175,830).

Measurements

Overall prevalence of recorded calcium and vitamin D use for osteoporosis prevention and treatment, and annual visit rates were estimated by age, gender, race, insurance types, physician specialties, geographical regions, and metropolitan status using chi square test. Multivariate logistic regression was conducted to determine potential predictive factors for calcium and vitamin D supplements.

Results

An increase in yearly trend of calcium and vitamin D supplements was observed. The increase was proportional to patients’ age (p<0.05) and female gender was a strong predictor of calcium and vitamin D supplement (p<0.0001).Visits made by blacks were significantly less likely to be associated with the supplement (p<0.05). Visits associated with self-pay and Medicaid was less likely to be recorded with vitamin D (p<0.05) but not calcium supplements. Osteoporosis diagnosis was an independent predictor of calcium and vitamin D records (p<0.0001).

Conclusions

In spite of the observed increases in the trend of visits associated with calcium and vitamin D supplements, variability in the access to the medications was observed. More focused strategies targeting elderly, men, or black population are needed to maintain and improve adequate calcium and vitamin D supplements.

     

Bladder Cancer is Associated with Low Plasma 25-hydroxyvitamin D Concentrations in Tunisian Population

Little evidence suggests an impact of vitamin D on bladder cancer risk in Caucasians. This study aimed to investigate association of plasma 25-hydroxyvitamin D (25-OHD) with urothelial bladder cancer (UBC) risk in Tunisians. A case-control study included 250 patients with UBC and 250 healthy controls. Plasma 25-OHD was assessed by a competitive chemiluminescence immunoassay. Vitamin D deficiency and insufficiency were defined as 25-OHD <30 nmol/L and 30 to 49.99 nmol/L, respectively. Logistic regression models adjusting for gender, age, smoking status, duration of smoking, occupational exposure, and season were applied. Vitamin D deficiency (50.4% vs. 34.8%; P < 0.001) and insufficiency (40.4% vs. 26.8%; P < 0.001) were more frequent in patients than controls. Multivariate analysis showed that UBC is associated with vitamin D deficiency [odd-ratio (95% confidence interval), 3.71 (1.76–7.80); P = 0.001] and vitamin D insufficiency [2.65 (1.40–5.01); P = 0.003]. Other predictors of UBC were female gender, tobacco use, smoking duration, and occupational exposure. Plasma 25-OHD concentrations are low in Tunisian patients with UBC. These findings support experimental and epidemiological evidence of protective role of vitamin D against UBC but could not ascertain causal relationship. Further prospective studies and clinical trials are warranted to check causality.     

The influence of renal function on vitamin D metabolism in the very elderly

Objectives

Hypovitaminosis D and chronic kidney disease (CKD) are highly prevalent in older adults. The factors correlating with 25-OH-vitamin D and PTH levels were analyzed in older adults with and without CKD.

Design

We performed a cross-sectional analysis embedded within the BELFRAIL study.

Setting

A population-based prospective cohort study of the very elderly in Belgium.

Participants

325 participants, all aged 80 or older.

Measurments

Time of year and LAPAQ score were used as proxies for sunshine exposure. Vitamin D3 supplementation, gender, institutionalisation, age, level of education, and serum calcium and phosphorus level were examined as possible confounders in the analyses.

Results

There was no correlation between the presence of CKD and low 25-OH-vitamin D levels, but there was a significant (p<0. 01) correlation between CKD and high PTH levels. Among the participants with a normal eGFR, the LAPACQ score, vitamin D supplementation, season, log PTH value and eGFR were correlated with log 25-OH-vitamin D levels. Among the participants with CKD, only vitamin D supplementation, log PTH levels and serum calcium levels were correlated with log 25-OH-vitamin D levels. Gender, log 25-OH-vitamin D values, serum calcium and phosphorus levels and eGFR were correlated with log PTH values in the patients with normal eGFR. Log 25-OH-vitamin D values, serum phosphorus levels, vitamin D supplementation (p=0.07), season (p=0.10) and eGFR were correlated with log PTH values in the patients with CKD.

Conclusion

Exposure to sunshine and an active lifestyle were correlated with higher 25-OH-vitamin D levels in older adults without CKD. The PTH level in patients with CKD may be influenced by the season.     

The oldest old: Red blood cell and plasma folate in African American and white octogenarians and centenarians in Georgia

Objective  

To determine the overall folate status of a population-based multi-ethnic sample of octogenarians and centenarians and the specific dietary, demographic and physiological factors associated with observed abnormalities.     

Vitamin D insufficiency among postmenopausal women in urban and rural areas in Guilan, Northern Iran

This study aimed to describe vitamin D status in postmenopausal women in urban and rural areas in Guilan, northern Iran. Between October 2004 and February 2005 a group of 750 women older than 50 years was randomly selected from urban and rural areas in Guilan. The participants were interviewed to collect data on age, educational level, body weight, height, employment status, reproductive history, medications, history of illness, and supplement use. Serum 25(OH) D was measured in 646 women (427 in urban areas and 219 women in rural areas). Serum 25(OH) D levels in urban and rural postmenopausal women were 18.5 ± 13.5 ng/ml and 22.9 ± 13.8 ng/ml (P < 0.0001), respectively. In urban and rural areas, 84.7% and 79.5% of the women had serum 25(OH) D levels less than 30 ng/ml, respectively. In this study, serum vitamin D levels and prevalence of vitamin D insufficiency was related to educational level in urban women. The urban women in the lowest educational level (<5 years schooling) had a better vitamin D status than other educational groups. This study showed that a high proportion of postmenopausal women living in Guilan province had vitamin D insufficiency. Vitamin D inadequacy was more common in urban areas and especially in the upper social class. Supplement use and national strategies to prevent vitamin D insufficiency are strongly needed in this community.     

Vitamin D Deficiency in Children With Intestinal Failure Receiving Home Parenteral Nutrition

Background: Vitamin D plays important roles in both skeletal and nonskeletal health. Limited data suggest that patients with intestinal failure (IF) receiving home parenteral nutrition (PN) are at risk for vitamin D deficiency due to inadequate oral intake, poor absorption, and chronic illness. The purpose of this study was to document vitamin D status in pediatric patients with IF receiving home PN. Materials and Methods: We performed a 2‐year retrospective review of children with IF followed at our center who had been on home PN for ≥6 months and had ≥1 serum 25‐hydroxyvitamin D (25‐OHD) level checked as part of routine clinical care. Patients were then categorized as deficient (<20 ng/mL), insufficient (20–29 ng/mL), or normal (≥30 ng/mL) based on their lowest vitamin D level. Demographic data and clinical characteristics were also assessed. Results: Eleven of 27 children (41%) had ≥1 insufficient 25‐OHD level, including one child with vitamin D deficiency. Diagnosis of short bowel syndrome (compared with dysmotility or malabsorption syndromes) was associated with decreased likelihood of suboptimal vitamin D status, with an odds ratio of 0.12 (95% confidence interval, 0.02–0.8, P = .028). Osteopenia was noted in 59% of the cohort. There was a trend toward higher risk for osteopenia in patients with low 25‐OHD levels compared with those with normal 25‐OHD levels (82% vs 44%, P = .109). Conclusion: Suboptimal 25‐OHD levels are common in children with IF on home PN. This emphasizes the critical importance of routine surveillance of serum vitamin D levels and consideration of enteral supplementation when indicated.     

Vitamin D Status in Malaysian Men and Its Associated Factors

Vitamin D insufficiency is a global health problem. The data on vitamin D status in Malaysian men is insufficient. This study aimed to investigate vitamin D status among Chinese and Malay men in Malaysia and its associating factors. A cross-sectional study was conducted on 383 men aged 20 years and above, residing in Klang Valley, Malaysia. Their age, ethnicity, body anthropometry and calcaneal speed of sound (SOS) were recorded. Their fasting blood was collected for serum 25-hydroxyvitamin D (25(OH)D), intact parathyroid (PTH), total calcium and inorganic phosphate assays. Vitamin D deficiency was defined as a serum 25(OH)D level <30 nmol/L and insufficiency as a serum 25(OH)D level between 30 and 50 nmol/L. The overall prevalence of vitamin D deficiency was 0.5%, and insufficiency was 22.7%. Vitamin D deficiency and insufficiency were more prevalent in the Malays compared to the Chinese. Being Chinese, older in age, having lower body mass index (BMI) and a high physical activity status were associated significantly with a higher serum 25(OH)D level (p < 0.05). The serum PTH level was inversely associated with the serum 25(OH)D level (p < 0.05). As a conclusion, a significant proportion of Malaysian men have vitamin D insufficiency, although deficiency is uncommon. Steps should be taken to correct the vitamin D status of these men.     

Association of modifiable and nonmodifiable factors with vitamin D status in pregnant women and neonates in Oakland, CA

There is little information on the contribution of modifiable vs nonmodifiable factors to maternal and neonatal vitamin D status in temperate regions of the United States. The purpose of this cross-sectional observation study conducted between December 2006 and February 2008 was to identify associations between observed and measured maternal characteristics and vitamin D status at term in pregnant women and their infants in a multiethnic community in Oakland, CA. Two hundred seventy-five pregnant women aged 18 to 45 years and carrying a singleton fetus were recruited and data from 210 mother-infant pairs were included in analyses. Analysis of covariance identified predictors of maternal and cord serum 25-hydroxyvitamin D [25(OH)D] in a multivariate model considering vitamin D intake, lifestyle factors, and skin pigmentation. Maternal serum 25(OH)D was significantly associated with season of delivery (P=0.0002), average daily D intake (P=0.0008), right upper inner arm pigmentation (P=0.0035), and maternal pre- or early-pregnancy body mass index (calculated as kg/m²) (P=0.0207). The same factors were significant for cord serum 25(OH)D, which was highly correlated with maternal serum 25(OH)D (r=0.79; P<0.0001). During the year, 54% of mothers and 90% of neonates had 25(OH)D <30 ng/mL (<75 nmol/L). Of women taking daily prenatal vitamin/mineral supplements (400 IU vitamin D), 50.7% had serum 25(OH)D <30 ng/mL (<75 nmol/L). In conclusion, 25(OH)D <30 ng/mL (<75 nmol/L) was prevalent in mothers and neonates across racial groups and seasons, and vitamin D status was associated with both modifiable and nonmodifiable risk factors.     

Vitamin D deficiency and insufficiency in the Georgia Older Americans Nutrition Program

Serum 25-hydroxyvitamin D (25(OH)D) status in older adults enrolled in community-based meal programs is not well characterized. The objective was to identify predictors of poor serum 25(OH)D status and the response to vitamin D supplementation in a convenience sample from the Older Americans Act Nutrition Program (OAANP) in northeast Georgia (N = 158, mean age = 77 years, 81% women, 69% Caucasian, 31% African American). Mean serum 25(OH)D was 55nmol/l, and intakes of vitamin D and calcium from foods were very low. Vitamin D insufficiency (25(OH)D 25- < 50 nmol/l) occurred in 36.7%. Vitamin D deficiency occurred in 8.2% (25(OH)D < 25 nmol/l) and was associated with low milk intake, low sunlight exposure, receiving meals at home, tobacco use, depression, dementia, antianxiety medication, poor instrumental activities of daily living, and low calf circumference (p < or = 0.05). When non-supplement users (n = 28) were given a multivitamin with vitamin D (10 microg/d) and calcium (450 mg/d) for 4 months, 25(OH)D increased from 50 to 78 nmol/l, the prevalence of poor vitamin D status (25(OH)D < 50 nmol/l) decreased from 61% to 14%, and serum alkaline phosphatase decreased by 10% (p < 0.01). High body weight appeared to attenuate the increase in 25(OH)D in response to the multivitamin supplement (p < or = 0.05). In conclusion, OAANP services did not prevent poor vitamin D and calcium status, but a supplement with vitamin D and calcium was beneficial.     

学龄儿童维生素D营养状况与跟骨骨密度关系的前瞻性队列研究

目的探讨学龄儿童维生素D营养状况与跟骨骨密度的关系。方法研究对象来自“儿童青少年心血管与骨健康促进项目”,于2017年采用分层整群抽样的方法在北京市对15391名6~16岁儿童开展基线调查,2019年对其进行随访调查。进行问卷调查,测量血清25(OH)D和跟骨超声骨密度(BMD)。采用多因素线性回归和logistic回归分析基线维生素D营养状况与随访期跟骨BMD及其变化的关系。结果纳入分析的10914名儿童的年龄为(11.5±3.3)岁,男童占49.6%,基线25(OH)D水平为(35.4±12.0)nmol/L,缺乏率为36.1%。多因素回归分析显示,校正年龄、性别、BMI、吸烟、饮酒、奶制品摄入、维生素D补充、钙剂补充、体力活动、青春期发育状态和基线跟骨BMD Z值后,25(OH)D每增加10 nmol/L,随访时点跟骨BMD Z值增加0.01(P=0.041),2年间发生跟骨BMD Z值下降的OR=0.96(95%CI:0.93~1.00),P=0.030;相对于维生素D充足,维生素D不足和缺乏的儿童随访时点跟骨BMD Z值下降0.03(P=0.307)和0.06(P=0.046),2年间跟骨BMD Z值下降的风险分别增加15%(P=0.037)和21%(P=0.006),趋势P值均<0.05。结论维生素D营养状况与跟骨BMD密切相关,维生素D充足的儿童倾向于获得更高的BMD水平。倡导儿童青少年维持充足的维生素D水平,加强营养与运动,促进骨骼健康。     

More on the zinc connection.

Background: Inadequate vitamin D nutritional status is increasingly recognized as common in North American and European populations, but the extent of the shortfall and the parameters of the distribution for populations of interest remain uncertain.

Purpose: To report the distribution of values for serum 25-hydroxyvitamin D [25(OH)D] in a population of rural postmenopausal women, together with quantification of factors related to vitamin D status.

Setting: Nine largely agrarian counties in eastern Nebraska (～41° N).

Participants: A population-based sample of 1,179 women 55 years of age and older recruited into a four-year trial of calcium and vitamin D supplementation.

Methods: Baseline biochemical, dietary, and anthropometric measurements obtained on entry into trial.

Results: Serum 25(OH)D concentration at baseline varied cyclically with season, with the solar cycle explaining 2.9% of the total variance (P < 0.001). Mean seasonally adjusted 25(OH)D concentration was 71.1 nmol/L. Serum 25(OH)D also exhibited the expected inverse curvilinear relationship with serum parathyroid hormone (PTH), with the inflection point of the curve located at approximately 80 nmol/L. Supplements containing vitamin D were regularly taken by 59% of the cohort (median dose: 200 IU/d). Nevertheless, approximately 4% of all women had values below the laboratory reference range and more than two-thirds fell below 80 nmol/L. Seasonally adjusted serum 25(OH)D concentration was positively correlated with the size of daily vitamin D supplement dose, and negatively with age, weight, and body mass index (P < 0.01 for all). In stepwise multiple linear regression models, weight, age, and supplement dose were independently correlated with seasonally adjusted serum 25(OH)D, and together explained 19% of the total variance of adjusted 25(OH)D concentration. Women taking supplements had only one-sixth the chance of having a 25(OH)D value below the reference limit of the assay, compared to women who did not use supplements.

Conclusions: Approximately two-thirds of this rural population fell below 80 nmol/L, a value considered to be the lower end of the optimal range. Based on the slope of 25(OH)D on supplement dose observed in these women, it would require an additional vitamin D input of nearly 2000 IU/d to reach the goal of an RDA for vitamin D, i.e., to bring 97.5% of the cohort to levels of 80 nmol/L or higher.     

Plasma 25-Hydroxyvitamin D Responses of Younger and Older Men to Three Weeks of Supplementation with 1800 IU/day of Vitamin D

Objective: The objective of this study was to compare changes in plasma 25-hydroxyvitamin D (25(OH)D) levels of younger and older men after three weeks of oral vitamin D supplementation.

Methods: Nine younger men (22 to 28 years) and nine older men (65 to 73 years) with self-reported vitamin D intakes below 200 IU/d were enrolled in February and randomized to 1800 IU/d of ergocalciferol (vitamin D₂, n=11) or to a control group (n=7) and followed for three weeks. Blood was collected at baseline, and after one, two and three weeks for measurement of plasma concentrations of total 25(OH)D, 25(OH)D₂ and 25(OH)D₃.

Results: In both the younger and older supplemented men, 25(OH)D₂ and total 25(OH)D concentrations increased significantly during the study, whereas values of these metabolites did not change in younger or older control subjects. No group showed significant changes in 25-hydroxyvitamin D₃. There was a significant interaction between age group and supplement group, suggesting that the effect of vitamin D₂ supplementation on changes in 25(OH)D₂ changes with age. The mean increase in 25(OH)D₂ was greater in the younger supplemented men than in the older supplemented men (37±9 nmol/L vs. 19.5 nmol/L, p=0.027), and this accounted for their significantly greater increase in total 25(OH)D.

Conclusion: These data are consistent with an age-related decline in the absorption, transport or liver hydroxylation of orally-consumed vitamin D.