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Physical performance and 25-hydroxyvitamin D: a cross-sectional study of pregnant Swedish and Somali immigrant women and new mothers
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Centre for Clinical Research, County of Västmanland. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Public Health and Caring Sciences, Family Medicine and Preventive Medicine.
2013 (English)In: BMC Pregnancy and Childbirth, ISSN 1471-2393, Vol. 13, 237- p.Article in journal (Refereed) Published
Abstract [en]


Severe vitamin D deficiency can impair muscle strength. The study aims were to examine physical performance in the hands and upper legs, and analyze plasma 25-hydroxyvitamin D (25(OH) D) concentrations in women with presumably low (veiled, Somali-born) and high levels (unveiled, Swedish-born).


Women (n = 123, 58% Swedish) enrolled at a Swedish antenatal clinic, latitude 60 degrees N, were recruited. Plasma 25(OH) D was analyzed, measured as nmol/L, then categorized as <10 = undetectable, 10-24, 25-49, 50-74 or >75. Muscle strength was tested: maximal hand grip strength (in Newtons, N), and upper leg performance (categorized as able/unable to perform squatting, standing on one leg, standing from a chair, and lifting their hips). Social and anthropometric data were collected. Non-parametric statistics tested the data for differences in their ability to perform the tests across 25(OH) D categories. Undetectable values (< 10 nmol/L) were replaced with '9' in the linear correlation statistics. A final main effect model for grip strength (in N) was calculated using stepwise linear regression for independent variables: country of birth, 25(OH) D levels, age, height, weight, physical activity, lactation status, parity, and gestational age.


Somali participants (35%) had 25(OH) D levels of < 10 nmol/L, and 90% had < 25 nmol/L; 10% of Swedish participants had < 25 nmol/L of 25(OH) D, and 54% had < 50 nmol/L. Somali women had a relatively weak grip strength compared with Swedish women: median 202 N (inter-quartile range 167-246) vs. median 316 N (inter-quartile range 278-359), respectively. Somali women were also weak in upper leg performance: 73% were unable to squat, 29% unable to stand on one leg, and 21% could not lift their hips (not significant across 25(OH) D categories); most Swedish women could perform these tests. In the final model, grip strength (N) was significantly associated with 25(OH) D levels (B 0.94, p=0.013) together with Somali birth (B -63.9, p<0.001), age (B 2.5, p=0.02) and height (B 2.6, p=0.01).


Many Somali women had undetectable/severely low 25(OH) D concentrations and pronounced hand and upper leg weakness; grip strength was strongly associated with 25(OH) D. Maternity health care personnel should be aware of this increased frequency and manage care accordingly.

Place, publisher, year, edition, pages
2013. Vol. 13, 237- p.
Keyword [en]
Vitamin D, 25(OH)D, Ultraviolet B radiation, Grip strength, Clinical observation, Physical performance, Primary care, Somalia, Pregnancy
National Category
Medical and Health Sciences
URN: urn:nbn:se:uu:diva-217631DOI: 10.1186/1471-2393-13-237ISI: 000329252000003OAI: oai:DiVA.org:uu-217631DiVA: diva2:694290
Available from: 2014-02-06 Created: 2014-02-04 Last updated: 2014-02-06Bibliographically approved

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Löfvander, Monica
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