Effect of vitamin D supplementation on bone and vitamin D status among Pakistani immigrants in Denmark: a randomised double-blinded placebo-controlled intervention study

Abstract

Severe vitamin D deficiency is common among Muslim immigrants. The dose necessary to correct the deficiency and its consequence for bone health are not known for immigrants. The aim was to assess the effect of relatively low dosages of supplemental vitamin D on vitamin D and bone status in Pakistani immigrants. This 1-year-long randomised double-blinded placebo-controlled intervention with vitamin D 3 (10 and 20 mg/d) included girls (10·1 -14·7 years), women (18·1 -52·7 years) and men (17·9 -63·5 years) of Pakistani origin living in Denmark. The main endpoints were serum 25-hydroxyvitamin D (S-25OHD), parathyroid hormone, bone turnover markers and bone mass. The study showed that supplementation with 10 and 20 mg vitamin D 3 per d increased S-25OHD concentrations similarly in vitamin D-deficient Pakistani women (4-fold), and that 10 mg increased S-25OHD concentrations 2-fold and 20 mg 3-fold in Pakistani men. S-25OHD concentrations increased at 6 months and were stable thereafter. Baseline S-25OHD concentrations tended to be lower in girls and women than in men; females achieved about 46 nmol/l and men 55 nmol/l after supplementation. Serum intact parathyroid hormone concentrations decreased at 6 months, but there was no significant effect of the intervention on bone turnover markers and dual-energy X-ray absorptiometry measurements of the whole body and lumbar spine. The large population groups living in a traditional Islamic cultural pattern in Europe are at major risk of vitamin D deficiency due to insufficient sun exposure and low vitamin D intake. Previously, in the cross-sectional part of this study, we found median 25-hydroxyvitamin D (25OHD) concentrations between 10·9 and 20·7 nmol/l among adolescent girls, premenopausal women and men with Pakistani origin living in Denmark (1) . Similar results have been reported in Norway (2 -5) and in the UK (6) . Clinical trials investigating the effect of vitamin D supplementation on fracture risk have shown conflicting results (7 -12) . Several of the trials combined Ca with vitamin D, making it unclear which nutrient is responsible for an observed effect. However, trials with vitamin D supplementation alone (dosages 10 -20 mg/d) also find conflicting results (10,11,13,14) . A meta-analysis of seven randomised trials found that fracture risk was reduced among ambulatory or institutionalised elderly individuals at vitamin D supplemental dosages of 17·5 -20 mg/d, but not at 10 mg/d (15) . However, this differs from a Cochrane review, which found fracture reduction among elderly institutionalised individuals given vitamin D and Ca, but the effect of vitamin D alone was unclear (16) . Bone mineral density (BMD) is a useful measure for predicting fracture risk (17,18) , and BMD was increased with vitamin D and Ca supplementation in some studies among elderly Caucasians (7 -9) and with vitamin D supplementation alone in other studies (19 -21) . Case reports show improvement in vitamin D status (and reduced muscle pain) by vitamin D supplementation among immigrants (...

Vitamin D supplementation does not affect serum lipids and lipoproteins in Pakistani immigrants

“…No significant effect of the 1-year long supplementation on any of the lipids was found; suggesting that vitamin D supplementation in small doses does not increase the risk of ischaemic heart disease in this group. The vitamin D supplementation was given to improve bone status; therefore, the power was calculated with regards to an increment in Bone Mineral Density (BMD) (Andersen et al, 2008a). Owing to the low vitamin D status at baseline (Table 1) (Andersen et al, 2008b), the 25-hydroxyvitamin D status only increased to about 45-54 nmol/l (Andersen et al, 2008a).…”

“…The local ethics committee and Danish Medicines Agency approved the study protocol (Andersen et al, 2008a), and the study was carried out in accordance with the Declaration of Helsinki. The written informed consent was obtained from all participants.…”

Association of body fat and vitamin D status and the effect of body fat on the response to vitamin D supplementation in Pakistani immigrants in Denmark

“…Further information about recruitment, tablets, sampling, compliance and biochemical analyses is described elsewhere. 8 Two different measures of body fat were used: body mass index (BMI) was calculated on the basis of anthropometric measures of weight and height (kg/m 2 ) and used as an indirect measure of body fat. Body fat mass and lean mass were measured by wholebody DXA scans from which the body fat percentage (fat mass/ (total weight) × 100%) was calculated.…”

Effect of vitamin D3-supplementation on bone markers (serum P1NP and CTX): A randomized, double blinded, placebo controlled trial among healthy immigrants living in Norway

“…High bone turnover in vitamin D deficient persons was seen in observational studies (Erkal et al, 2006, Islam et al, 2008, Macdonald et al, 2008). However, the few intervention studies examining the effect of vitamin D supplementation on bone turnover in population such as Caucasian postmenopausal women, young adults and immigrants with low vitamin status have produced mixed results (Grimnes et al, 2012, Macdonald et al, 2013, Andersen et al, 2008). A one year randomized double-blinded placebo-controlled intervention with vitamin D 3 (10 and 20 μg/d) in young women and men of Pakistani origin living in Denmark showed that supplementation increased serum 25(OH)D concentrations and decreased serum parathyroid hormone (PTH) concentrations but there was no significant effect of the intervention on bone turnover markers (Andersen et al, 2008).…”

“…However, the few intervention studies examining the effect of vitamin D supplementation on bone turnover in population such as Caucasian postmenopausal women, young adults and immigrants with low vitamin status have produced mixed results (Grimnes et al, 2012, Macdonald et al, 2013, Andersen et al, 2008). A one year randomized double-blinded placebo-controlled intervention with vitamin D 3 (10 and 20 μg/d) in young women and men of Pakistani origin living in Denmark showed that supplementation increased serum 25(OH)D concentrations and decreased serum parathyroid hormone (PTH) concentrations but there was no significant effect of the intervention on bone turnover markers (Andersen et al, 2008). In another randomized trial, four weeks of daily supplementation with 10 μg vitamin D 3 decreased mean PTH but surprisingly increased tartrate-resistant acid phosphatase (s-TRACP, which is a bone resorption marker) concentration in healthy adults 19–48 years of ethnic Norwegian and Tamil background (Holvik et al, 2012).…”