Pakistani Immigrant Children and Adults in Denmark Have Severely Low Vitamin D Status

European Journal of Clinical Nutrition (2008) 62, 625–634 & 2008 Nature Publishing Group All rights reserved 0954-3007/08 $30.00 www.nature.com/ejcn ORIGINAL ARTICLE Pakistani immigrant children and adults in Denmark have severely low vitamin D status R Andersen1, C Mølgaard2, LT Skovgaard3, C Brot1, KD Cashman4, J Jakobsen5, C Lamberg-Allardt6 and L Ovesen1 1Department of Nutrition, National Food Institute, Technical University of Denmark, Søborg, Denmark; 2Department of Human Nutrition, Faculty of Life Sciences, University of Copenhagen, Frederiksberg, Denmark; 3Department of Biostatistics, University of Copenhagen, Copenhagen, Denmark; 4Department of Food Science and Technology, University College Cork, Cork, Ireland; 5Department of Chemistry, National Food Institute, Technical University of Denmark, Søborg, Denmark and 6Division of Nutrition, University of Helsinki, Helsinki, Finland 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 (551N), 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 ¼ 0.04) and women (P ¼ 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. European Journal of Clinical Nutrition (2008) 62, 625–634; doi:10.1038/sj.ejcn.1602753; published online 18 April 2007 Keywords: vitamin D status; 25-hydroxyvitamin D; bone status; bone turnover markers; Pakistani immigrants; Denmark Introduction facilitate the absorption of calcium and phosphorus in the gut to maintain blood calcium concentrations that are vital Vitamin D is a primary regulator of calcium homoeostasis to proper bone mineralization. Vitamin D deficiency can and bone metabolism. The active metabolites of vitamin D result in rickets in children, and in osteomalacia and/or osteoporosis in adults and elderly (Heaney, 2003; Zitter- Correspondence: R Andersen, Department of Nutrition, National Food Institute, Technical University of Denmark, Mørkhøj Bygade 19, DK-2860 mann, 2003). Since the main source of vitamin D is Søborg, Denmark. ultraviolet light, reduced sun exposure, due to clothing E-mail: [email protected] habits, dark skin pigmentation or living at northern Guarantor: R Andersen. latitudes, can lead to vitamin D deficiency. Diet is a Contributors: RA collected the data, wrote the manuscript and undertook the statistical analyses with advice from LTS, CM and LO. RA, CB, KDC, CL-A, CM secondary source of vitamin D, since only few foods contain and LO designed the study. JJ undertook the measurements of S-25OHD. KDC significant amounts of vitamin D. undertook the measurements of bone turnover markers. CL-A undertook the In the late 1960s and early 1970s Pakistani men moved to measurements of S-iPTH, calcium and phosphate. All contributed to the Denmark as labour immigrants. Many of the immigrants manuscript. Received 27 April 2006; revised 5 March 2007; accepted 8 March 2007; settled down and have now lived in Denmark for about 30 published online 18 April 2007 years with their family and descendants. Presently about Severely low vitamin D status among Pakistanis in Denmark R Andersen et al 626 313 100 people from non-Western countries live in Den- (immigrants or descendants with Pakistani parents) primarily mark, and about 19 250 of these are of Pakistani origin living in the Copenhagen area, Denmark (551N). About 87% (immigrants and descendants) (Statistics Denmark, 2005). of all the Pakistanis in Denmark live in the Copenhagen area People who migrate from sun-rich countries to countries (Statistics Denmark, 2005). that are sun-deprived for half of the year and have low UV- The recruitment began in January 2002. Few subjects were intensity even at summer (e.g., Denmark) may increase their recruited during the first quarter (10%), and the recruitment risk of vitamin D deficiency. In particular, when the habit of strategy was intensified during the spring. Therefore, most avoiding direct sun exposure is maintained and most of the subjects (80%) were recruited during the second and third skin is covered with clothes also during the summer, the quarter of 2002, which is the season in Denmark with deficiency may become severe. vitamin D-producing UV radiation. An extra effort was made In recent studies from Norway (Meyer et al., 2004; Holvik to recruit more men during September–October, and the last et al., 2005) vitamin D deficiency was prevalent among 10% (mainly men) were recruited during these months. The Pakistani adults (mean serum 25-hydroxyvitamin D (S- recruitment ended in November, since fasting blood sam- 25OHD): 21–25 nmol/l), but serious deficiency was not pling is not possible during the Muslim Ramadan (which associated with reduced bone mineral density among the took place during November–December in 2002). Pakistani women (Falch and Steihaug, 2000; Meyer et al., The subjects were recruited through information meetings 2004). Two other studies from Oslo, Norway, found that at schools, mosques, cricket clubs, private organizations, vitamin D deficiency (mean S-25OHD: 15–19 nmol/l) was etc.; adverts in local Pakistani newspapers, local Pakistani common among pregnant Pakistani women (Brunvand and radio and television and posters in relevant places, since the Haug, 1993; Henriksen et al., 1995). Rickets and osteomalacia Danish National Central Offices of Civil Registrations do not have been described among Asian immigrants in the UK contain information about ethnic origin. Consequently, the for several years (Dunnigan et al., 1962; Hunt et al., 1976; sample is not random and the representativeness of the Henderson et al., 1987; Nisbet et al., 1990; Finch et al., 1992; sample could not be assessed due to lack of information Solanki et al., 1995; Serhan and Holland, 2002). In Denmark, about non-acceptors. vitamin D deficiency (mean S-25OHD 7 nmol/l) is found Among a total of 295 subjects signing up for participation among Arab women (Glerup et al., 2000a, b), however people 247 (37 girls, 115 women, 95 men) participated at the of Pakistani origin have not been investigated. Besides, little baseline visit including interview, blood and urine sampling. is known about vitamin D status of immigrant children and The number of subjects corresponds to 4.2, 2.3 and 1.5%, men. respectively, of all the Pakistani girls, women and men living The aim of this study was to determine the vitamin D and in Denmark at corresponding ages (Statistics Denmark, bone status in healthy adolescent girls, pre-menopausal 2005). The setting was the Danish Food and Veterinary women and men of Pakistani origin (immigrants or descen- Administration (now the National Food Institute). dants) living in Denmark, and to determine the association Exclusion criteria were medications and diseases known between the vitamin D status, bone metabolism and bone to affect bone metabolism or S-25OHD concentrations, status. Besides, to identify the most important risk factors for pregnancy and breast-feeding. The women were tested for vitamin D deficiency among the Pakistanis, the determi- pregnancy before dual energy X-ray absorptiometry (DXA) nants of vitamin D status were investigated for the adults. scanning. One pregnant and one post-menopausal woman and one man with lymphoma were excluded. Subjects with incomplete data in one or more of the explanatory variables Subjects and methods were excluded in the multiple regression analyses, and they did not differ significantly from the study population with The study is the baseline part of a 1-year long double-blinded respect to S-25OHD and the available explanatory variables. randomized placebo-controlled intervention study with two doses of vitamin D (10 and 20 mg/day). The local ethic committee approved the study protocol Biochemical sampling and analyses (Reg. No. KA01101g). The study was carried out in accor- Morning blood samples were taken by venipuncture after dance with the Declaration of Helsinki. Written informed an overnight fast. Local anaesthetic patches were offered to consent was obtained from all participants, as well as from the girls to reduce the discomfort of venipuncture. Blood the parents/guardians of the girls. samples were centrifuged (approximately 3000 g for 10 min.) within 2 hours of sampling, and serum was frozen and stored at À801C. Morning second void urine samples were collected Subjects after an overnight fast. Urine samples were frozen and stored The subjects were adolescent girls (median age 12.2 years, at À201C. range 10.1–14.7), pre-menopausal women (median age 36.2 S-25OHD concentrations (vitamin D2 plus D3 are used years, range 18.1–52.7) and men (median age 38.3 years, here, since D2 was only detected in four subjects) were range 17.9–63.5).

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