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Little is known about the effect of working conditions on vitamin D status in Southeast Asia, where vitamin D deficiency is common despite the presence of sunlight all year round in most places. We examined the prevalence of vitamin D deficiency and its associated work-related factors among indoor workers using the data of 213 participants (aged &ge, 21 years) from a workplace cohort study in Singapore. Vitamin D deficiency was defined as serum 25-hydroxyvitamin D (25(OH)D) concentration &lt, 50 nmol/L. Data on work-related factors, socio-demographic characteristics, and lifestyle habits were collected using standardized questionnaires. Clinical and biochemical measurements were performed using standard tools and protocols. Multivariate Poisson regression was used to examine the independent association of work-related factors with vitamin D deficiency. Mean serum 25(OH)D concentration was 59.6 nmol/L. The prevalence of vitamin D deficiency was 32.9% (95% confidence interval (CI): 26.6&ndash, 39.6%). In the multivariate analysis, office workers (prevalence ratio (PR): 2.16, 95% CI: 1.12&ndash, 4.16 versus control room workers), workshop workers (PR: 2.25, 95% CI: 1.05&ndash, 4.81 versus control room workers), and night shift workers (PR: 1.31, 95% CI: 1.03&ndash, 1.67) were at a greater risk for vitamin D deficiency. Workplace policies and wellness programs should encourage workers to take regular breaks to go outdoors for sunlight exposure and to consume adequate amounts of vitamin D-rich foods to maintain optimal vitamin D levels.

We aimed to examine the behavioural and clinical risk factors for non-communicable diseases (NCDs) at baseline and their changes over 12 months in a workplace cohort in Singapore. A total of 464 full-time employees (age &ge, 21 years) were recruited from a variety of occupational settings, including offices, control rooms, and workshops. Of these, 424 (91.4%) were followed-up at three months and 334 (72.0%) were followed up at 12 months. Standardized questionnaires were used to collect data on health behaviours and clinical measurements were performed by trained staff using standard instruments and protocols. Age-adjusted changes in risk factors over time were examined using generalized estimating equations or linear mixed-effects models where appropriate. The mean age of the participants at baseline was 39.0 (SD: 11.4) years and 79.5% were men. Nearly a quarter (24.4%) were current smokers, slightly more than half (53.5%) were alcohol drinkers, two-thirds (66%) were consuming &lt, 5 servings of fruit and vegetables per day, and 23.1% were physically inactive. More than two-thirds (67%) were overweight or obese and 34.5% had central obesity. The mean follow-up was 8.6 months. After adjusting for age, over 12 months, there was a significant increase in the proportion consuming &lt, 5 servings of fruit and vegetables per day by 33% (p = 0.030), who were physically inactive by 64% (p &lt, 0.001), and of overweight or obese people by 15% (p = 0.018). The burden of several key NCD risk factors at baseline was high and some worsened within a short period of time in this working population. There is a need for more targeted strategies for behaviour change towards a healthy lifestyle as part of the ongoing health and wellness programs at workplaces in Singapore.

Underground workplaces are an important element in modern urban planning. As a result, an increasing but unquantified proportion of the population is being regularly exposed to them. We narratively reviewed the literature on the range of possible environmental exposures, and the possible health effects, to identify future research directions. There is a large but mainly observational research literature on likely underground exposures, including effects of artificial lighting, shift working and light at night on circadian disruptions and associated health effects. There are five studies comparing underground and aboveground environments. Shift working, artificial lighting and poor sleep quality leading to circadian disruption is one physiologic pathway. Working underground may increase exposure to these risks, and may also be associated with vitamin D deficiency, sick building syndrome, excessive noise, radon exposure, and negative psychological effects. In order to plan appropriate interventions, we need to expand our knowledge of the health effects of underground environments. Larger and longer-term studies are required to measure a range of human factors, environmental exposures and confounders. Controlled trials with health economic analyses of new lighting technologies are also required. NRF (Natl Research Foundation, S’pore) Accepted version