Vitamin D level and its association with adiposity among multi ethnic teachers in Wilayah Persekutuan Kuala Lumpur, Malaysia / Intan Shafinaz Sharifudin
Vitamin D plays an essential role in health. Its deficiency can not only increase the risk of osteoporosis, but also contribute to cardiovascular diseases, diabetes and certain types of cancers. Skin synthesis of vitamin D from sunlight exposure constitutes the major source of vitamin D. Evide...
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| Format: | Thesis |
| Published: |
2016
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| Online Access: | http://studentsrepo.um.edu.my/7088/7/intan.pdf http://studentsrepo.um.edu.my/7088/ |
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| Summary: | Vitamin D plays an essential role in health. Its deficiency can not only increase the
risk of osteoporosis, but also contribute to cardiovascular diseases, diabetes and certain
types of cancers. Skin synthesis of vitamin D from sunlight exposure constitutes the
major source of vitamin D. Evidences showed that not only temperate countries
experience the problem of vitamin D deficiency, but a similar problem exists in tropical
countries like Malaysia, Indonesia, Saudi Arabia and Tehran. Currently, there are new
evidences that show obesity may contribute to vitamin D deficiency. Obesity-associated
vitamin D deficiency is most likely due to the decreased bioavailability of vitamin D3
because of its deposition in the body fat compartments.
The aim of this study was to identify the risk factors contributing to a low serum
25(OH)D level and its association with adiposity among secondary school teachers in
the state of Wilayah Persekutuan Kuala Lumpur (WPKL). This was a cross sectional
study of two-stage sampling conducted from February 2013 to May 2013. First, 50%
out of a total of 80 government day schools in WPKL were randomly selected from
each district in Pudu, Bangsar, Sentul and Keramat respectively. Then, all teachers from
the selected schools who fulfilled the inclusion criteria of the study were invited to
participate. Ethics clearance was obtained from the University Malaya Medical Centre
(UMMC) Ethics Committee (Reference Number: 950.1). Approval from the Ministry of
Education, Education Board of Wilayah Persekutuan Kuala Lumpur (WPKL) and
principals from each selected schools were obtained before data collection. Informed
consent was obtained from all participants. The data collection included serum 25
hydroxyvitamin D (25(OH)D), Parathyroid Hormone (PTH), blood glucose, fat
percentage, waist circumference and Body Mass Index (BMI). Demographic
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characteristics, sun exposure and avoidance, and level of physical activity were also
collected using a self-administered questionnaire.
A total of 858 participants were recruited. The majority of them were Malays,
females and married. The overall prevalence of vitamin D deficiency (<20 ng/ml) was
67.4%. Indian (80.9%) participants had the highest proportion of vitamin D deficiency,
followed by Malays (75.6%), others (44.9%) and Chinese (25.1%). There was a
significant negative association between serum 25(OH)D level with BMI (β= -0.23) and
body fat percentage (β= -0.14). In the multivariate linear regression analysis; Malays,
Indians, females (p<0.001), higher BMI and larger waist circumference (p<0.05) were
significantly associated with lower serum 25(OH)D level. The full model explained
32.8% of variation contributing to serum 25(OH)D level among the participants.
Adiposity explained only less than 1% of the variability of serum 25(OH)D level. The
two most influential factors affecting serum 25(OH)D level were ethnicity and sex.
Health education should be targeted in weight management, sex based behaviors on sun
exposure and avoidance, as skin pigmentation is non-modifiable. |
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