3 days ago Research undertaken by Boots Vitamins found residents of three UK cities are most at risk of becoming deficient in the essential vitamin this. Vitamin D deficiency is pandemic, yet it is the most under-diagnosed Vitamin D 3 is produced in the skin on exposure to sunlight. Recent studies have linked vitamin D deficiency with increased risk of . Relatively, fish are a rich source of vitamin D. The residents of Bengal (eastern India) eat more fish. The prevalence of vitamin D deficiency was high in a sunny city—Isfahan— include poor bone development and health and also increased risk of many common India, and Iran because of low exposure to sun due to cultural factors ().
of THESE most D cities deficiency Vitamin risk Residents at THREE deficiency: are of
Those who refused to take part in the study were excluded. During the study, 1, healthy residents of Isfahan, aged years, were studied. Their mean age was Calcium and phosphate concentrations were normally distributed.
The median range level of OHD was 21 4. The prevalence of vitamin D deficiency was compared in the age-groups of , , and years. In autumn-winter, mild, moderate and severe vitamin D deficiencies were prevalent among In spring-summer, mild, moderate and severe vitamin D deficiencies were prevalent among Prevalence of vitamin D insufficiency and deficiency in spring, summer, autumn, and winter.
The normal range for calcium in our laboratory was 8. The mean age of this subgroup was 41 median 13 years. The mean concentrations of their calcium and phosphate were 8.
The results of the study in Isfahan, a sunny city located in the central part of Iran, confirms the high prevalence of vitamin D deficiency However, there is no significant difference in vitamin D insufficiency between men and women.
Although Isfahan is a sunny city, direct exposure to sun is, however, limited. According to legislation, all women are required to wear a scarf and long-sleeve clothes. This is why they have more severe vitamin D deficiency. On the other hand, most men wear long-sleeve shirts, especially those who work in governmental administrations.
Fear from skin cancer encourages people to use anti-solar creams on their face. Living in apartments which is increasing due to increased population of the country and tendency to live in big cities are among other factors which restrict exposure to sun in Iran. The calcium level in 66 of the 1, study population was of less than normal ranges, which may be due to vitamin D deficiency.
The median range of OHD in this subgroup was 22 1. Thus, the cause of hypocalcaemia in some persons may not be related to vitamin D deficiency. However, the median concentration of OHD in the 66 persons was within vitamin D deficiency or at least insufficiency range. Vitamin D deficiency is the most common medical condition worldwide.
An estimated one billion people in the world have vitamin D deficiency or insufficiency 1. Several studies in different parts of Iran and in different age-groups have shown the high prevalence of vitamin D deficiency 13 - In a similar study in Tehran among the general population, aged years. Despite the fact that direct comparisons of results of different studies are difficult due to the use of different methods for the measurement of OHD concentrations and that different definitions for vitamin D deficiency have been used, the findings of our study indicate that the rate of severe vitamin D deficiency status has an increasing trend.
In a study in Norway among five main immigrant groups, including Iranians, the median serum OHD levels were The prevalence of mild, moderate and severe vitamin D deficiencies was The mean serum OHD concentration was In the present study, both median OHD concentration and prevalence of vitamin D deficiency but not insufficiency were more prevalent among women than among men. Although other studies reported similar results in this field, it, however, seems that factors involved in vitamin D deficiency may be different more between men and women in some ethnic groups than others.
Other factors are outdoor activity and clothing habits veiling. Many studies have demonstrated that the rate of vitamin D deficiency in veiled women was higher 25 - In our study, the prevalence of vitamin D deficiency was much higher among the younger age-group whereas most studies reported the higher prevalence of vitamin D deficiency among the elderly people 28 - 30 , It may be due to supplementation of vitamin D among elderly people, especially women, who are getting used to taking multivitamin tablets.
Younger people prefer living in apartments and have less outdoor physical activity whereas older people prefer living in houses and have had more outdoor physical activity when they were younger and also now.
We did not measure height and weight of the population studied. It is one of the pitfalls of our study. If we had these parameters and calculated their BMI and its relationship with vitamin D status, it would have explained why older people have higher concentration of vitamin D.
However, more studies are needed to clarify the cause. In this study, median of vitamin D was higher in summer than in winter Fig. This finding indicates that season as an environmental factor could have effect on the severe form of vitamin D deficiency. Several studies have demonstrated that vitamin D deficiency and mean of low vitamin D level have been higher in winter. According to the study of Kull et al. It seems that factors, such as style of clothing, air pollution, skin pigmentation, and insufficient vitamin D intake, lack of routine enrichment of foods with vitamin D in Iran, could be responsible for the findings of our study 14 , However, not measuring the dietary vitamin D intake, duration of exposure to sunlight, and other possible risk factors for vitamin D deficiency are among the limitations of our study.
Based on the findings of the study, we recommend fortification of foods with vitamin D to treat and prevent vitamin D deficiency as the styles of clothing and other lifestyle factors are not expected to be changed in the present time. The authors thank Dr. Conway for her help in English editing of the manuscript. National Center for Biotechnology Information , U. J Health Popul Nutr. Author information Copyright and License information Disclaimer.
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This article has been cited by other articles in PMC. Abstract Determination of vitamin D status in different age-groups in a community and in different climates of a country is necessary and has important implications for general health. Biochemical parameters Sampling was performed between 8: Statistical analysis Normality of data distribution was assessed with Kolmogrov-Smirnov.
Ethical issues All the study subjects gave voluntary informed consent before participation. Open in a separate window. Prevalence of vitamin D deficiency The prevalence of mild, moderate and severe vitamin D deficiencies among the adult population was Cut-off point for vitamin D deficiency according to level of PTH. Participants completed detailed questionnaires regarding their typical nutritional intake and physical activity during the previous year, including an assessment of calcium and vitamin D intake dietary and supplements and participation in sports and other activities, as described previously.
One blood sample 15 mL was obtained for each subject at the end of the health visit. All tests were performed in the hospital clinical laboratory using kits provided by the same manufacturer Nichols Institute, San Clemente, Calif. The samples were analyzed in multiple assays. Interassay coefficients of variation were 5. The patients were divided into 3 diagnostic categories according to their serum 25OHD concentrations, as rounded to the nearest integer. In increasing order of severity, the 25OHD levels were as follows: The definition of vitamin D insufficiency has been used previously in adults 2 , 22 and children.
The ultimate prevalence estimate was The serum 25OHD level showed a skewed distribution and was accordingly log transformed for analysis, to prevent undue influence of extreme values. Milk consumption of more than 1. We constructed a multiple regression model for 25OHD level using all predictors of interest, whether significant or not in simple regression. We identified confounding relationships by adding or removing a suspected confounder and observing the effect on statistical significance of the remaining variables in the model.
From the final multiple regression model, we derived effect size estimates in the form of regression coefficients for the continuous predictors and scalar contrasts between levels or pertinent combinations of levels for the dichotomous eg, sex and polytomous eg, season predictors.
The effects in log units change in log 25OHD level were converted to percentage units for reporting: The final sample was composed of subjects Table 1. Serum calcium, phosphorus, and magnesium levels were normal.
Hypovitaminosis D was also most prevalent during winter and spring compared with summer and fall Figure 1. There was no significant difference in prevalence between adolescent girls and boys There were significant relationships between consumption of selected food items and vitamin D deficiency Table 3. There was a positive correlation between vitamin D deficiency and consumption of soft drinks, fruit juice, and iced tea, and an inverse correlation between the deficiency and consumption of milk and cold cereal commonly fortified with vitamin D.
There was no significant correlation between vitamin D deficiency and consumption of yogurt, cheese, or ice cream Table 3. Box plot of seasonal variation in serum hydroxyvitamin D 25OHD level. The mean winter 25OHD level was significantly lower than that during summer, and concentrations between summer and fall and between winter and spring were similar.
To convert 25OHD to nanomoles per liter, multiply by 2. Relationship between serum hydroxyvitamin D 25OHD and parathyroid hormone levels. Sex and activity showed a weak nonsignificant relation to 25OHD concentration in bivariate analyses. Both were retained for further examination in multiple regression analysis because of suspected confounding relationships to milk consumption and season, respectively.
Outdoor and total activity levels showed no relation to 25OHD level, and were not considered further. To provide a basis for interpretation of potential confounding relationships in multiple regression results, we examined the associations among predictor variables.
We found a significant interaction between milk consumption and season, with the effect of milk consumption being significant during winter and spring but not during summer and fall. An examination of alternative models confirmed that the gain in significance for activity was attributable to adjustment for season, which removed the confounding due to lower activity levels in summer. We found a high prevalence of vitamin D deficiency among otherwise healthy adolescents in a convenience sample from an urban adolescent clinic.
These findings add to growing data, including findings from the Third National Health and Nutrition Examination Survey and cohorts of adolescent girls in Bangor, Maine, and Cleveland, Ohio, 12 , 23 , 24 suggesting that this nutritional deficiency is a prevalent problem among the pediatric age group, as has been previously documented in adults.
To our knowledge, this is the first study to examine the prevalence of this problem in adolescent boys and girls throughout the year, in particular adolescents in the northeastern United States during the winter when the high latitude of Boston may preclude cutaneous synthesis of vitamin D. These data are similar to findings from 4 previous studies 2 , 5 , 11 , 22 of young and elderly Boston adults. Thus, these findings suggest that vitamin D deficiency is a problem spanning the age spectrum, particularly among African American adolescents and residents of a northern latitude.
Dietary and seasonal issues may explain the high prevalence of this nutritional deficiency among our otherwise healthy teenagers. Low levels of UV light exposure occur during winter in Boston, 20 likely explaining the seasonal variation observed. On this basis, 2 groups 25 , 26 have suggested that children in extreme northern or southern latitudes receive supplementation. Dietary factors may have also contributed. Milk consumption, an independent predictor of 25OHD levels, has decreased over recent years in children and adolescents, and with it, the adequate intake of calcium and vitamin D.
A recent study 28 found that US women with low milk intake during childhood had a lower bone mass during adulthood and a higher risk of fracture, suggesting skeletal implications of this trend. The recent availability of vitamin D—fortified juices may help to alleviate this problem. We also found that use of multivitamins, preparations routinely containing vitamin D, was strikingly low in our clinic sample, and was lowest among African American patients.
Although bone turnover markers were not measured in this study, hypovitaminosis D was accompanied by secondary hyperparathyroidism, potentially leading to increased bone resorption, the physiological significance of which is unknown in adolescents. In addition to the present findings in these adolescents, this relationship exists in elderly persons, 19 , 20 , 29 healthy adults, 2 adult inpatients, 11 female outpatients, 21 children in Lebanon, 6 and adolescent boys in France.
We found that African American adolescents were more likely to have hypovitaminosis D than teenagers of other ethnic groups. The effects of sunlight exposure on vitamin D synthesis are decreased in individuals with darker skin pigmentation and in sunscreen users. Looker et al 12 found vitamin D deficiency most frequently in US non-Hispanic African American subjects, especially during winter in their study sites within the southern United States.
Data for the Third National Health and Nutrition Examination Survey were collected during winter in the southern United States and during summer in the northern United States, preventing estimation of the prevalence of vitamin D deficiency in individuals living in the northeastern United States during winter, as was afforded by the present study.
Similarly, another study 34 showed the highest rate of hypovitaminosis D among African American women of reproductive age, complementing reports 35 of a high prevalence of nutritional rickets in African American breastfed infants.
These findings confirm that more information is needed regarding appropriate screening practices and indications for supplementation for adolescents across ethnic groups. Because African American youth have been shown to have a higher bone density compared with other groups, 36 the long-term skeletal and other consequences of these findings deserve further study.
As shown in recent studies 37 , 38 of adults, we found an inverse correlation between body mass index and serum 25OHD concentration. Even after controlling for ethnicity, sex, and consumption of milk and juice, the body mass index remained an independent predictor of hypovitaminosis D in our final multivariate model. A study 39 of adults showed that obesity-associated vitamin D insufficiency is likely due to the decreased vitamin D bioavailability from cutaneous and dietary sources because of its deposition in body fat.
In light of findings from adult studies and the increase of obesity among youth, the present data suggest a need to consider body mass index in the formulation of pediatric recommendations in this area. These findings must be interpreted in light of acknowledged limitations. First, the study was cross-sectional and, therefore, causality cannot be inferred. Only a longitudinal study will be able to confirm that the identified correlates are definite risk factors for hypovitaminosis D and to determine whether vitamin D supplementation has significant beneficial health effects in adolescents.
Second, the present study sample was enriched in subgroups known to be at higher risk for low vitamin D levels, including African American, Hispanic, and overweight teenagers; this may limit the generalizability of these findings.
Nevertheless, even in our subgroup of white adolescents whose risk for vitamin D deficiency is lower, the prevalence of this problem still exceeded our predetermined level of concern. The present study group may also not be representative of Boston adolescents because of other unidentified causes of referral bias. We did not use a validated tool to measure sun exposure, an important predictor of serum 25OHD level.
Although we obtained information on weekly outdoor activities, this measure provided only indirect information regarding sun exposure in these individuals, and no association was found between this variable and 25OHD concentration.
In addition, we did not obtain information regarding sunscreen use, another potential confounder influencing cutaneous vitamin D synthesis. However, there were patients in whom the 25OHD concentration was subnormal, but the finding was not accompanied by secondary hyperparathyroidism, the clinical significance of which is unknown in young patients and deserves further study. Last, information on nutrition and activity was obtained by self-report in adolescents, with its inherent limitations.
In conclusion, we found a high prevalence of vitamin D deficiency in a sample of otherwise healthy US teenagers seen for primary care in an urban northeastern outpatient clinic.
Even after adjusting for the ethnic distribution of teenagers in the United States, our estimated prevalence was still twice what we predetermined would be clinically significant. The association between hypovitaminosis D and dietary vitamin D and milk consumption suggests that attention should be paid to optimizing an adolescent's vitamin D intake, either by diet or supplementation.
Prevalence of Vitamin D Deficiency among Adult Population of Isfahan City, Iran
“Many studies also have linked vitamin D [deficiency] to cardiovascular disease, on the face, arms, legs, or back without sunscreen between 10 am and 3 pm at in Pediatrics found that “overall, 9% of the pediatric population, representing Children at high risk of vitamin D deficiency likely will need higher levels of . Scientific American is the essential guide to the most awe-inspiring Three- quarters of U.S. teens and adults are deficient in vitamin D, the. M.H. Edwards1,4, Z.A. Cole1,4, N.C. Harvey1, C. Cooper1,2,3 Severe vitamin D deficiency causes new bone, the osteoid, not to be mineralized. . The very elderly population has been found to be a group a particular risk of vitamin D Hypovitaminosis D among healthy adolescent girls attending an inner city school.