Physical performance and 25-hydroxyvitamin D: a cross-sectional study of pregnant Swedish and Somali immigrant women and new mothers.
BMC Pregnancy Childbirth. 2013 Dec 17;13(1):237.
Kalliokoski P, Bergqvist Y, Löfvander M.
BACKGROUND: 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).
METHODS: Women (n=123, 58% Swedish) enrolled at a Swedish antenatal clinic, latitude 60 [degree sign] 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.
- (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 1.7, p=0.01)
CONCLUSIONS: 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.
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- Search VitaminDWiki for "Grip Strength" 57 items Dec 2013
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- Higher vitamin D during pregnancy associated with stronger hand grip at age 4 – Oct 2013
- Muscle strength not increased by raising vitamin D to only 30 ng – RCT Aug 2012
- Overview Sports and vitamin D
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- Hypothesis: Why so many females in the Middle East are now Vitamin D Deficient
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- Dark skinned pregnant women far from equator were very vitamin D deficient – Sept 2012
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- Overview Middle East and vitamin D
- The following is from Hypothesis: Why so many females in the Middle East are now Vitamin D Deficient
Based on reading about dress codes for women and recently seeing the movie Wadjda , which is set in Saudia Arabia
- Dress codes started when living in tribes and women may have only needed to cover themselves when there were outside male visitors
Plenty of access to the sun most of the time
- Dress codes continued when people moved to cities
Women still got vitamin D in courtyards or rooftops - not wear excessive clothes when men from the family could not see them
Even being in the shade the women would get about 1/3 the amount of vitamin D/hour
- Air conditioning became prevalent in the last portion of the 20th century, allowing people to escape the heat
Rate of Multiple Sclerosis in women has gone up 6X in the past 30 years in Tehran (MS is strongly related to lack of vitamin D)
- Predict that rickets will make its appearance soon in the Middle East
Turkey managed to reduce rate of rickets by 60X by giving 400 IU of vitamin D to EVERY child
Hajab prevalence: Wikipedia
- Ethnicity, Clothing Style And Body Mass Index Are Significant Predictors Of Vitamin D Insufficiency In Germany Oct 2014
Turkish women in Germany were 3.6 X more likely to have low vitamin D(<30 ng)when they wore covered clothing