Pakistani immigrant children and adults in Denmark have severely low vitamin D status

OBJECTIVE: To determine vitamin D and bone status in adolescent girls, pre-menopausal women and men of Pakistani origin, to single out determinants of vitamin D status and to determine the association between vitamin D status, bone metabolism and bone status. SUBJECTS/METHODS: Cross-sectional study, Copenhagen (55 degrees N), January-November. Serum 25-hydroxyvitamin D (S-25OHD), serum intact parathyroid hormone (S-iPTH), bone turnover markers and whole body and lumbar spine bone mineral density were measured. Sun, smoking and clothing habits, age, body mass index (BMI), and vitamin D and calcium from food and from supplements were recorded. Thirty-seven girls (median age, range: 12.2 years, 10.1-14.7), 115 women (36.2 years, 18.1-52.7) and 95 men (38.3 years, 17.9-63.5) of Pakistani origin (immigrants or descendants with Pakistani parents) took part in the study. RESULTS: Median concentration of S-25OHD was 10.9, 12.0 and 20.7 nmol/l for girls, women and men, respectively. Forty-seven per cent of the girls, 37% of the women and 24% of the men had elevated S-iPTH, and there was a negative relationship between S-iPTH and S-25OHD. Use of vitamin D-containing supplements had a positive association with S-25OHD for men (P=0.04) and women (P=0.0008). Twenty-one per cent of the women and 34% of the men had osteopenia. Neither S-25OHD nor S-iPTH was associated with lumbar spine or whole body bone mineral content. CONCLUSIONS: Severely low vitamin D status and elevated S-iPTH is common among Pakistani immigrants in Denmark. The low vitamin D status is not associated with bone markers or bone mass among relatively young Pakistanis.     

Prevalence of vitamin D deficiency and secondary hyperparathyroidism during winter in pre-menopausal Bangladeshi and Somali immigrant and ethnic Finnish women: associations with forearm bone mineral density

Secondary hyperparathyroidism (SHPT) is one of the outcomes of vitamin D deficiency that negatively affects bone metabolism. We studied the ethnic differences in vitamin D status in Finland and its effect on serum intact parathyroid hormone (S-iPTH) concentration and bone traits. The study was done in the Helsinki area (60°N) during January-February 2008. A total of 143 healthy women (20-48 years of age) from two groups of immigrant women (Bangladeshi, n 34 and Somali, n 48), and a group of ethnic Finnish women (n 61) were studied in a cross-sectional setting. Serum concentrations of 25-hydroxyvitamin D (S-25OHD) and S-iPTH were measured. Peripheral quantitative computed tomography measurements were taken at 4 and 66?% of the forearm length. In all groups, the distribution of S-25OHD was shifted towards the lower limit of the normal range. A high prevalence of vitamin D insufficiency (S-25OHD?65?ng/l) was higher (79·1?%) in Somali women than in Finnish women (16?%). There was a significant association between S-25OHD and S-iPTH (r?-?0·49, P?相似文献   

Teenage girls and elderly women living in northern Europe have low winter vitamin D status

OBJECTIVE: To determine the vitamin D status (serum 25-hydroxyvitamin D; S-25OHD) in adolescent girls and elderly community-dwelling women living in four countries of northern Europe and to explain differences in S-25OHD concentrations between and within the countries. DESIGN: A cross-sectional observational study conducted in a standardised way during February-March. S-25OHD was analysed by high-performance liquid chromatography. Vitamin D and calcium intake was calculated using a standardised food composition database. SETTING: Denmark, Finland, Ireland, and Poland. SUBJECTS: A total of 199 girls (mean (s.d.) age 12.6 (0.5) y) and 221 women (mean (s.d.) age 71.8 (1.4) y). RESULTS: The median (inter quartiles) concentration of S-25OHD was 29.4 (20.3, 38.3) nmol/l for the girls and 40.7 (28.0, 54.2) nmol/l for the women. S-25OHD below 25 nmol/l was found in 37% of the girls and 17% of the women, and S-25OHD below 50 nmol/l was found in 92% of the girls and 37% of the women. Positive significant determinants for S-25OHD in girls were use of vitamin D supplements, and in women sun habits, dietary vitamin D intake, use of vitamin D and calcium supplements. Body mass index and smoking were negative determinants in women. For women predictors could explain the differences between countries (P(country) = 0.09, R(2) = 0.39), but for girls the difference remained significant even after including predictors (P(country) = 0.03, R(2) = 0.15). CONCLUSION: Vitamin D status is low in northern Europe during winter. More than one-third of the adolescent girls have vitamin D status below 25 nmol/l and almost all are below 50 nmol/l. Two-thirds of the elderly community-dwelling women have vitamin D status below 50 nmol/l. Use of vitamin D supplements is a significant positive determinant for S-25OHD for both girls and women (P = 0.001). SPONSORSHIP: The European Fifth Framework Programme (Contract No. QLK1-CT-2000-00623).     

Plasma vitamin D and 25OHD responses of young and old men to supplementation with vitamin D3

OBJECTIVES: This study was conducted to determine whether there are age differences in the plasma parent vitamin D and 25-hydroxyvitamin D (25OHD) responses to eight weeks of supplementation with 20 microg/day of vitamin D3. METHODS: Twenty-five healthy young men (age 18-35) and 25 healthy older men (62-79) were randomly assigned to supplementation with 20 microg/day of vitamin D3 or to no intervention and followed for eight weeks. Plasma vitamin D3 was measured by high performance liquid chromatography and 25OHD was measured by competitive protein binding. RESULTS: Both young and old men in the supplemented group had pronounced, rapid and similar increases in plasma vitamin D3, whereas vitamin D3 concentrations were stable in the control group. By the end of the eight-week adaptation period, plasma vitamin D3 of young and old men had increased by 4.3 and 6.2 nmol/L respectively. In the supplemented group, mean 25OHD concentrations of both the young and old men increased during the study, and the magnitude of the change after eight weeks was nearly identical in the two age groups (22.5 and 22.1 nmol/L in the young and the old men, respectively). In the control group there was a modest decrease in 25OHD of both the young and old men. CONCLUSIONS: There appears to be no age-related impairment among men in the absorption or metabolism of 20 microg/day of vitamin D3 taken orally for at least eight weeks.     

Vitamin D deficiency and hyperparathyroidism in relation to ethnicity: a cross-sectional survey in healthy adults

Background  The study of vitamin D status at population level gained relevance since vitamin D deficiency was recently suggested to trigger chronic disease. Aim of the study  We aimed to describe vitamin D status, its association with bone and mineral metabolism and risk factors for deficiency in adults over 40 years in Belgium. Methods  We conducted a cross-sectional survey in a stratified random sample of 401 subjects aged between 40 and 60 years living in Brussels, and drawn from 4 different ethnic backgrounds: autochthonous Belgian, Moroccan, Turkish and Congolese. 25-Hydroxyvitamin D (25OHD), parathyroid hormone (PTH), osteocalcin, C-telopeptide and bone mineral density was measured. Results  Three-hundred and six subjects (77%) showed 25OHD concentrations below 50 nmol/l,135 (34%) below 25 nmol/l and 18 (5%) below 12.5 nmol/l. The proportion of subjects with vitamin D deficiency was four times greater amongst those of Moroccan or Turkish descent compared with those of Congolese or Belgian descent. Moroccan subjects showed a significant higher PTH and bone marker concentrations compared to Belgian. Ethnicity, season and sex were independently associated with vitamin D deficiency in multivariate analysis. Conclusion  The prevalence of vitamin D deficiency is very high amongst the adult population of Brussels but immigrants are at greater risk. Given the established link between population health and adequate vitamin D status, a policy of vitamin D supplementation should be considered in these risk groups.     

Effect of vitamin D supplementation on vitamin D status and bone turnover markers in young adults

OBJECTIVE: To assess the vitamin D status of healthy young people living in Northern Ireland and the effect of vitamin D supplementation on vitamin D status and bone turnover. DESIGN: Double-blinded randomised controlled intervention study. SETTING: University of Ulster, Coleraine, Northern Ireland. SUBJECTS: In total, 30 apparently healthy students (15 male and 15 female subjects), aged 18-27 years, were recruited from the university, with 27 completing the intervention. INTERVENTIONS: Subjects were randomly assigned, to receive either 15 microg (600 IU) vitamin D(3) and 1,500 mg calcium/day (vitamin D group), or 1,500 mg calcium/day (control group) for 8 weeks between January and March. Vitamin D status, bone turnover markers, serum calcium and parathyroid hormone concentrations were measured at baseline and post intervention. RESULTS: At baseline, vitamin D status was low in both the vitamin D group (47.9 (s.d. 16.0)) and the control group (55.5 (s.d. 18.6) nmol/l 25(OH)D). Post intervention vitamin D status was significantly higher in the vitamin D-treated group (86.5 (s.d. 24.5)) compared to the control group (48.3 (s.d. 16.8) nmol/l) (P<0.0001). There was no significant effect of supplementation on bone turnover markers or PTH concentrations. CONCLUSIONS: This study suggests that young adults in Northern Ireland do not consume an adequate daily dietary intake of vitamin D to maintain plasma vitamin D concentrations in the wintertime. A daily supplement of 15 microg vitamin D(3) significantly increased vitamin D status in these individuals to levels of sufficiency. Achievement of an optimum vitamin D status among young adults may have future positive health implications.     

Low vitamin D status adversely affects bone health parameters in adolescents

BACKGROUND: The effects of subclinical vitamin D deficiency on bone mineral density (BMD) and bone turnover in adolescents, especially in boys, are unclear. OBJECTIVE: We aimed to investigate the relations of different stages of vitamin D status and BMD and bone turnover in a representative sample of adolescent boys and girls. DESIGN: BMD was measured by dual-energy X-ray absorptiometry at the nondominant forearm and dominant heel in a random sample of 12- (n = 260) and 15-y-old (n = 239) boys and 12- (n = 266) and 15-y-old (n = 250) girls. Serum 25-hydroxyvitamin D, parathyroid hormone, osteocalcin, and type I collagen cross-linked C-telopeptide were assessed by using enzyme-linked immunoassays. Relations between vitamin D status and bone health indexes were assessed by using regression modeling. RESULTS: Using multivariate regression to adjust for potential physical, lifestyle, and dietary confounding factors, we observed that 12- and 15-y-old girls with high vitamin D status (>/=74.1 nmol/L) had significantly greater forearm (but not heel) BMD (beta = 0.018; SE = 0.008; P < 0.05 for each age group) and lower serum parathyroid hormone concentrations and bone turnover markers than did those with low vitamin D status. These associations were evident in subjects sampled throughout the year and in winter only. There was no significant relation between vitamin D status and BMD in boys. CONCLUSIONS: Maintaining serum 25-hydroxyvitamin D concentrations above approximately 50 nmol/L throughout the year may be a cost-effective means of improving bone health. Increased emphasis on exploring strategies for improving vitamin D status in adolescents is needed.     

Postpartum vitamin D insufficiency and secondary hyperparathyroidism in healthy Danish women

OBJECTIVE: To examine vitamin D status and parathyroid function in normal Danish women postpartum. DESIGN: Three cross-sectional measures during follow-up of 89 women postpartum. SUBJECTS AND INTERVENTION: We assessed vitamin D status by measuring plasma 25-hydroxyvitamin D (P-25OHD) and the degree of secondary hyperparathyroidism by measuring plasma parathyroid hormone (P-PTH) in 89 Caucasian women at three consecutive visits: (mean (range)) 23 (10-37) days (spring), 117 (95-140) days (late summer) and 274 (254-323) days (winter) postpartum. RESULTS: P-25OHD showed seasonal variations with higher values in late summer than in the other periods (P < 0.001). At the first visit, 65% received vitamin D supplements. At the following visits, almost 50% were supplemented. Vitamin D insufficiency (P-25OHD < 50 nmol/l) occurred more often during winter (28%) than in spring (14%) (Fisher's exact test, P = 0.02) or late summer (7%) (P = 0.0001). Irrespective of season, vitamin D insufficiency occurred most frequent in women who did not take vitamin D supplements (Fisher's exact test, P < 0.02). Frank vitamin D deficiency (P-25OHD < 25 nmol/l) was observed during winter in 6%. At all three periods, P-25OHD correlated inversely with P-PTH indicating secondary hyperparathyroidism at deficient vitamin D status. During spring, late summer and winter three, one and four females, respectively, had elevated plasma PTH. CONCLUSION: Vitamin D insufficiency with secondary hyperparathyroidism is a frequent finding in healthy Danish women postpartum and especially during winter. Vitamin D supplements reduced the risk of vitamin D insufficiency, especially during winter. Our results support the importance of increased alertness regarding information of pregnant and lactating women about vitamin D supplements. Furthermore, it has to be studied whether the present recommendations of an intake of 5-10 microg vitamin D/day are sufficient, especially during winter months.     

Vitamin D status and its relationship with parathyroid hormone and bone mineral status in older adolescents

Osteoporosis is an important contributor to the global burden of disease, and in the UK alone results in one in three women and one in twelve men aged >50 years experiencing a fragility fracture. Optimising peak bone mass in early adulthood is thought to reduce osteoporosis risk by offsetting bone losses in later life. Ensuring sufficient vitamin D status (measured as 25-hydroxyvitamin D (25OHD) in plasma), among other factors, is believed to facilitate the achievement of optimum peak bone mass. Lower 25OHD is associated with a higher plasma concentration of parathyroid hormone (PTH). As PTH is associated with increased bone turnover and bone loss, maintenance of sufficient 25OHD is thought to have a protective effect on bone health. However, there is a lack of consensus internationally on what constitutes an optimum 25OHD concentration, and values between 30 and 80 nmol/l have been suggested. These values have been based on findings from various studies in adults in which PTH has been observed to plateau at a 25OHD concentration of >30 nmol/l; however, not all studies have found such a plateau. Although studies in younger adolescents (14-16 years) have shown an inverse relationship between PTH and 25OHD, the concentration of 25OHD required for achievement of optimum peak bone mass is unknown. The present review examines the evidence defining vitamin D insufficiency thresholds, and the relevance of such thresholds to adolescent bone health.     

Vitamin D2 dose required to rapidly increase 25OHD levels in osteoporotic women

OBJECTIVE: Assessment of the effectiveness and safety of high daily 125 microg (5,000 IU) or 250 microg (10,000IU) doses of vitamin D(2) during 3 months, in rapidly obtaining adequate 25 hydroxyvitamin D (25OHD) levels. DESIGN: Longitudinal study. SUBJECTS: Postmenopausal osteopenic/osteoporotic women (n = 38) were studied during winter and spring. Median age (25-75th percentile) was 61.5 (57.00-66.25) years, and mean bone mineral density (BMD) was 0.902 (0.800-1.042)g/cm(2). Subjects were randomly divided into three groups: control group (n=13): no vitamin D(2), 125 mug/day (n=13) and 250 microg/day (n=12) of vitamin D(2) groups, all receiving 500 mg calcium/day. Serum calcium, phosphate, bone alkaline phosphatase (BAP), C-telopeptide (CTX), 25OHD, mid-molecule parathyroid hormone (mmPTH), daily urinary calcium and creatinine excretion were determined at baseline and monthly. RESULTS: For all subjects (n=38), the median baseline 25 hydroxyvitamin D (25OHD) level was 36.25 (27.5-48.12) nmol/l. After 3 months, 8% of the patients in the control group, 50% in the 125 microg/day group and 75% in the 250 microg/day group had 25OHD values above 85 nmol/l (34 ng/ml). Considering both vitamin D(2) groups together, mmPTH and BAP levels diminished significantly after 3 months (P<0.02), unlike those of CTX. Serum calcium remained within normal range during the follow-up. CONCLUSIONS: The oral dose of vitamin D(2) required to rapidly achieve adequate levels of 25OHD is seemingly much higher than the usual recommended vitamin D(3) dose (20 mug/day). During 3 months, 250 microg/day of vitamin D(2) most effectively raised 25OHD levels to 85 nmol/l in 75% of the postmenopausal osteopenic/osteoporotic women treated.     

The effect of conventional vitamin D(2) supplementation on serum 25(OH)D concentration is weak among peripubertal Finnish girls: a 3-y prospective study

OBJECTIVES: To study the effect of vitamin D supplementation and the impact of summer season on serum 25-hydroxyvitamin D (S-25(OH)D) in Finnish 9-15-y-old girls. DESIGN: Three-year follow-up study with vitamin D(2) supplementation using D(2) 10 microg daily from October to January for the first and from October to February for the second winter as well as 20 microg daily from October to March for the third winter. SETTING: Paavo Nurmi Centre, University of Turku, Turku, Finland. SUBJECTS: A total of 171 female volunteers aged 9-15 y. METHODS: Vitamin D and calcium intakes were estimated by a semi-quantitative food frequency questionnaire (FFQ). S-25(OH)D was measured by radioimmunoassay. RESULTS: The median daily dietary intakes of vitamin D and calcium were 3.8 microg (interquartile range (IQR) 2.7-5.0) and 1451 mg (IQR 1196-1812), respectively, over 3 y. The prevalence of severe hypovitaminosis D (S-25(OH)D<20 nmol/l) was 14% and of moderate hypovitaminosis D (20 nmol/l < or = S-25(OH)D < or = 37.5 nmol/l) 75% at baseline in winter. None of the participants had severe hypovitaminosis D in summer. The effect of 10 microg of D(2) daily was insufficient to raise S-25(OH)D from baseline. The daily supplementation of 20 microg of D(2) increased S-25(OH)D significantly in wintertime compared with the non-supplement users (to 45.5 vs 31.8 nmol/l; P<0.001). None of the subjects with vitamin D(2) supplementation approximately 20 microg daily had severe hypovitaminosis D; however, 38% of those participants had moderate hypovitaminosis D at 36 months. Sun exposure in summer raised mean S-25(OH)D to 62.0 nmol/l. Both the daily supplementation of approximately 20 microg of D(2) and summer sunlight exposure had more effect on those who had severe hypovitaminosis than those who had a normal vitamin D status (increase of 24.2 vs 0.9 nmol/l (P<0.001), and 38.8 vs 18.2 nmol/l (P<0.001), respectively). CONCLUSION: Vitamin D supplementation daily with 20 microg is needed to prevent hypovitaminosis D in peripubertal Finnish girls in winter. Sunlight exposure in summer is more effective than approximately 20 microg of D(2) supplementation daily in winter to raise S-25(OH)D. Both the daily supplementation with 20 microg of D(2) and summertime sunlight exposure had more effect on those who had severe hypovitaminosis D than those who had a normal vitamin D status. SPONSORSHIP: Supported by the Yrj? Jahnsson Foundation and the Medical Research Foundation of the Turku University Central Hospital.     

Dose response to vitamin D supplementation among postmenopausal African American women

BACKGROUND: Reports on the dose response to vitamin D are conflicting, and most data were derived from white men and women. OBJECTIVE: The objective was to determine the response of serum 25-hydroxyvitamin D [25(OH)D] to oral vitamin D(3) supplementation in an African American population. DESIGN: Healthy black postmenopausal women (n = 208) participated in a vitamin D(3) supplementation trial for a period of 3 y. Analyses were done in the vitamin D supplementation arm (n = 104) to quantify the response in serum 25-hydroxyvitamin D concentrations at a steady state vitamin D input. The participants received 20 microg/d (800 IU) oral vitamin D(3) for the initial 2 y and 50 microg/d (2000 IU) for the third year. RESULTS: Supplementation with 20 microg/d (800 IU/d) vitamin D(3) raised the mean serum 25(OH)D concentration from a baseline of 46.9 +/- 20.6 nmol/L to 71.4 +/- 21.5 nmol/L at 3 mo. The mean (+/-SD) concentration of serum 25(OH)D was 87.3 +/- 27.0 nmol/L 3 mo after supplementation increased to 50 microg/d (2000 IU/d). All participants achieved a serum 25(OH)D concentration >35 nmol/L, 95% achieved a concentration >50 nmol/L, but only 60% achieved a concentration >75 nmol/L. All patients had concentrations <153 nmol/L. On the basis of our findings, an algorithm for prescribing vitamin D so that patients reach optimal serum concentrations was developed. The algorithm suggests a dose of 70 microg (2800 IU/d) for those with a concentration >45 nmol/L and a dose of 100 microg (4000 IU/d) for those with a concentration <45 nmol/L. CONCLUSIONS: Supplementation with 50 microg/d (2000 IU/d) oral vitamin D(3) is sufficient to raise serum 25-hydroxyvitamin D concentrations to >50 nmol/L in almost all postmenopausal African American women. However, higher doses were needed to achieve concentrations >75 nmol/L in many women in this population.     

Maternal vitamin D status and delivery by cesarean

We examined the association of vitamin D deficiency to risk of cesarean delivery using prospective data in a cohort of 1153 low income and minority gravidae. Circulating maternal 25-hydroxyvitamin D and intact parathyroid hormone were measured at entry to care 13.73 ± 5.6 weeks (mean ± SD). Intake of vitamin D and calcium was assessed at three time points during pregnancy. Using recent Institute of Medicine guidelines, 10.8% of the gravidae were at risk of vitamin D deficiency, and 23.8% at risk of insufficiency. Maternal 25-hydroxyvitamin D was related positively to vitamin D and calcium intakes and negatively to circulating concentrations of parathyroid hormone. Risk for cesarean delivery was increased significantly for vitamin D deficient women; there was no increased risk for gravidae at risk of insufficiency. When specific indications were examined, vitamin D deficiency was linked to a 2-fold increased risk of cesarean for prolonged labor. Results were the similar when prior guidelines for vitamin D deficiency (25(OH)D < 37.5nmol/L) and insufficiency (37.5-80 nmol/L) were utilized.     

How much vitamin D3 do the elderly need?

BACKGROUND: Vitamin D insufficiency poses a problem in many parts of the world, the elderly being an especially vulnerable group. This insufficiency results from an inadequate amount of sunshine and a low dietary intake of vitamin D. Typically, insufficiency is accompanied with high intact parathyroid hormone, (S-iPTH) concentrations. AIMS OF THE STUDY: We studied how serum 25-hydroxy vitamin D (S-25-OHD) concentrations respond to different doses of vitamin D3 supplementation. Secondly to determine the smallest efficient dose to maintain serum 25-OHD concentration above the insufficiency level. We also studied which dose would be efficient in decreasing S-iPTH concentration in these subjects. SUBJECTS AND METHODS: Forty-nine 65- to 85-year-old women participated. The women were randomly assigned into one of four groups receiving 0 (placebo), 5, 10 or 20 microg of vitamin D3 daily for 12 weeks. Fasting morning blood was drawn at the beginning of the study, and thereafter every second week. Calciotropic variables were assessed from serum and urine samples. RESULTS: The S-25-OHD concentration increased significantly (p < 0.001) in all supplemented groups [5 microg: by 10.9 (8.5) nmol/L, 10 microg: by 14.4 (6.9) nmol/L, 20 microg: by 23.7 (11.9) nmol/L], whereas it decreased in the placebo group by 8.3 (13.2) nmol/L. Equilibrium in S-25-OHD concentration was reached in all groups after 6 weeks of supplementation at 57.7 (8.9) nmol/L, 59.9 (8.9) nmol/L and 70.9 (8.9) nmol/L in the groups with increasing vitamin D supplementation. The dose-response to supplementation decreased with increasing vitamin D status at baseline, r = -0.513, p = 0.002. S-iPTH tended to decrease in those with highest dose response to supplementation. CONCLUSIONS: A clear dose response was noted in S-25-OHD to different doses of vitamin D3. The recommended dietary intake of 15 microg is adequate to maintain the S-25-OHD concentration around 40-55 nmol/L during winter, but if the optimal S-25-OHD is higher than that even higher vitamin D intakes are needed. Interestingly, subjects with lower vitamin D status at baseline responded more efficiently to supplementation than those with more adequate status.     

Fortification of food with vitamin D is a reasonable approach to fracture prophylaxis

Vitamin-D deficiency is common in immobile elderly and non-Western immigrants and has been related to muscle weakness in these populations. When serum calcidiol concentrations are below 50 nmol/l, parathyroid hormone concentrations increase, causing bone resorption. Bone mineral density and proximal muscle strength increase as the serum concentration ofcalcidiol increases. Vitamin-D supplementation is reported to reduce the incidence of fractures in nursing home residents. Dutch guidelines recommend vitamin-D supplementation for nursing home residents and for those who are house-bound. Fortification of milk and other foods with vitamin D in the United States and Sweden has led to a better nutritional state with respect to vitamin D than in the Netherlands. Therefore the dairy industry should be allowed to add vitamin D to dairy products to prevent fractures.     

25-Hydroxyvitamin D: functional outcomes in infants and young children

Vitamin D deficiency occurs in the United States in exclusively breastfed infants who have high levels of skin pigmentation, inadequate vitamin D supplementation, and insufficient sunlight exposure. I review serum 25-hydroxyvitamin D [25(OH)D] concentrations and functional outcomes of vitamin deficiency in young children and breastfed and nonbreastfed infants. These outcomes include the presence or absence of vitamin D deficiency rickets, bone mineral content, and serum parathyroid hormone concentration. Daily vitamin D supplements of 400 IU/L keep serum 25(OH)D concentrations higher than 50 nmol/L and prevent rickets in infants and young children. The available evidence is not sufficient to support the use of bone mineral content or parathyroid hormone concentrations in infants and young children as functional outcomes to define deficient or sufficient levels of 25(OH)D. I therefore propose a research agenda to establish the functional definitions of vitamin D sufficiency or deficiency in infants and young children.     

Vitamin D intake is low and hypovitaminosis D common in healthy 9- to 15-year-old Finnish girls.

OBJECTIVES: To study the prevalence of hypovitaminosis D, the effect of vitamin D supplementation on serum 25-hydroxyvitamin D [S-25(OH)D], and the intakes of vitamin D and calcium in Finnish 9- to 15-year-old athletic and nonathletic girls. DESIGN: 1-year follow-up study (February 1997-March 1998) with three months of vitamin D supplementation (10 microg/d) from October to January. SETTING: Turku University Central Hospital, Finland. SUBJECTS: 191 female volunteers aged 9-15 y (131 athletes and 60 controls). METHODS: Vitamin D and calcium intakes were estimated by a four-day food recording and a semi-quantitative food frequency questionnaire (FFQ). S-25(OH)D was followed by radioimmunoassay (RIA). RESULTS: At baseline the mean S-25(OH)D concentration was 33.9 nmol/l among all girls. In winter severe hypovitaminosis D (S-25(OH)D < 20 nmol/l) occurred in 13.4% of the participants and in 67.7% S-25(OH)D was below 37.5 nmol/l. By the next summer the mean S-25(OH)D concentration was 62.9 nmol/l and in 1.6% of the subjects it was below 37.5 nmol/l. The prevalence of severe hypovitaminosis D was not significantly reduced by three months of vitamin D (10 microg/d) supplementation. At baseline, the mean intake of vitamin D was 2.9 microg/d by food recording and 4.3 microg/d by FFQ. The mean calcium intake was 1256 mg/d and 1580 mg/d, respectively. The intakes of vitamin D and calcium remained unchanged during the follow-up period. The athletes consumed more calcium than nonathletic controls, whereas the intake of vitamin D was quite similar among both groups. The vitamin D intake by FFQ correlated with the S-25(OH)D concentration in wintertime (r = 0.28, P < 0.01). CONCLUSION: Hypovitaminosis D is fairly common in growing Finnish girls in the wintertime, and three months of vitamin D supplementation with 10 microg/d was insufficient in preventing hypovitaminosis D. The daily dietary vitamin D intake was insufficient (< 5 microg/d) in the majority of participants, while the calcium intake was usually sufficient.     

Prospective study on food fortification with vitamin D among adolescent females in Finland: minor effects

Vitamin D insufficiency is common particularly during winter time. After the recommendation by the Ministry of Social Affairs and Health, Finnish fluid milks and margarines have been fortified with vitamin D since February 2003. The aims of the present study were to examine the impact of vitamin D fortification of food supplies on serum 25-hydroxyvitamin D (S-25(OH)D) concentrations and on daily dietary vitamin D intake among adolescent females. One hundred and forty-two girls of Caucasian ethnicity aged 12-18 years completed semi-quantitative FFQ from which the dietary vitamin D and Ca intakes were calculated. S-25(OH)D was measured by radioimmunoassay. The study was performed from February-March 2000 to February-March 2004, one year after the initiation of fortification. The mean dietary intake of vitamin D was < 7.5 microg in 91.5 % of the adolescent girls in 2000 and 83.8 % in 2004. The midwinter mean S-25(OH)D concentration did not change significantly during the follow-up period (48.3 v. 48.1 nmol/l, NS). The proportion of participants who had S-25(OH)D concentration < 50 nmol/l was 60.6 % in 2000 and 65.5 % in 2004. Only 7.0 % of the participants had an adequate S-25(OH)D ( >or= 75 nmol/l) level in 2000 or 4 years later. The vitamin D fortification of fluid milks and margarines was inadequate to prevent vitamin D insufficiency. There are numerous adolescent girls and women who are not reached by the current fortification policy. Therefore new innovative and feasible ways of improving vitamin D nutrition are urged.     

Vitamin D status and its adequacy in healthy Danish perimenopausal women: relationships to dietary intake, sun exposure and serum parathyroid hormone

We conducted this study to assess the prevalence of vitamin D insufficiency in a population of normal perimenopausal women, to examine the influence of sun exposure and vitamin D intake on the concentration of 25-hydroxyvitamin D (25OHD) and to examine the association between parathyroid hormone (PTH) and 25OHD. A total of 2016 healthy women aged 45-58, who had recently undergone a natural menopause, were enrolled over a 2.5-year period in the Danish Osteoporosis Prevention Study. A marked seasonal fluctuation of 25OHD was seen, with an abrupt rise in June and high values until October. The fluctuation could be related to number of hours of sunshine per month with a two months time lag. Dietary vitamin D intake, vitamin supplementation, sunlight exposure, and use of sun-bed were all significantly related to 25OHD concentrations. Sun exposure seemed to contribute the most. The overall prevalence of vitamin D deficiency (defined as serum ) was 7 %. However, in the subgroup avoiding direct sunshine and abstaining from vitamin D supplementation 32.8 % were vitamin D deficient in the winter-spring period. Although mean PTH was increased in the group with low serum 25OHD, PTH was not a sensitive marker of hypovitaminosis D in the individual, as only 16 % of those with vitamin D deficiency had PTH levels above normal range. Thus, we have shown, that healthy middle-aged Danish women are prone to vitamin D insufficiency in the winter-spring period, if they avoid sun exposure in the summer period and abstain from vitamin D supplementation.     

Vitamin D deficiency and low bone status in adult female garment factory workers in Bangladesh

The manufacture of garments is the main industry in Bangladesh and employs 1.6 million female workers. Due to the indoor lifestyle and low dietary intake of calcium, we hypothesised that they are at risk of low vitamin D and bone mineral status. Two hundred female garment workers (aged 18-36 years) were randomly selected. Serum 25-hydroxyvitamin D (S-25OHD), serum intact parathyroid hormone (S-iPTH), serum calcium (S-Ca), serum phosphate (S-P) concentration and serum alkaline phosphatase activity (S-ALP) were measured from fasting samples. Bone indexes of hip and spine were measured by dual-energy X-ray absorptiometry. The mean S-25OHD (36.7 nmol/l) was low compared to that recommended for vitamin D sufficiency. About 16% of the subjects were found to be vitamin D-deficient (S-25OHD 21 ng/l) was associated with progressive reduction in bone mineral density at the femoral neck and lumbar spine. According to the WHO criteria, the mean T-score of the femoral neck and lumbar spine of the subjects were within osteopenic range. We observed that subjects with a bone mineral density T-score < -2.5 had a trend of lower values of BMI, waist-hip circumference, mid-upper-arm circumference, S-25OHD and higher S-iPTH and S-ALP. The high prevalence of hypovitaminosis D and low bone mineral density among these subjects are indicative of higher risk for osteomalacia or osteoporosis and fracture.