Regional variation and determinants of vitamin D status in sunshine-abundant Thailand

Abstract

BackgroundVitamin D insufficiency is highly prevalent. Most of the studies concerning vitamin D status were generated from countries situated at temperate latitudes. It is less clear what the extent of vitamin D insufficiency is in countries situated in the tropics and how geographical regions within country would affect vitamin D status. In the present study, we investigated vitamin D status in Thais according to geographical regions and other risk factors.MethodsSubjects consisted of 2,641 adults, aged 15 - 98 years, randomly selected from the Thai 4th National Health Examination Survey (2008-9) cohort. Serum 25 hydroxyvitamin D were measured by liquid chromatography/tandem mass spectrometry. Data were expressed as mean ± SE.ResultsSubjects residing in Bangkok, the capital city of Thailand, had lower 25(OH)D levels than other parts of the country (Bangkok, central, northern, northeastern and southern regions: 64.8 ± 0.7, 79.5 ± 1.1, 81.7 ± 1.2, 82.2 ± 0.8 and 78.3 ± 1.3 nmol/L, respectively; p < 0.001). Within each region, except for the northeastern part of the country, subjects living inside municipal areas had lower circulating 25(OH)D (central, 77.0 ± 20.9 nmol/L vs 85.0 ± 22.1 nmol/L, p < 0.001; north 79.3 ± 22.1 nmol/L vs 86.8 ± 21.8 nmol/L, p < 0.001; northeast 84.1 ± 23.3 nmol/L vs 87.3 ± 20.9 nmol/L, p = 0.001; south, 76.6 ± 20.5 nmol/L vs 85.2 ± 24.7 nmol/L, p < 0.001). Overall, the prevalence of vitamin D insufficiency was 64.6%, 46.7%, and 33.5% in Bangkok, municipal areas except Bangkok, and outside municipal area in other parts of the country, respectively. In addition, the prevalence of vitamin D insufficiency according to geographical regions was 43.1%, 39.1%, 34.2% and 43.8% in the central, north, northeast and south, respectively. After controlling for covariates in multiple linear regression analysis, the results showed that low serum 25(OH)D levels were associated with being female, younger age, living in urban and Bangkok.ConclusionsVitamin D insufficiency is common and varies across geographical regions in Thailand.

Risk factors for osteoporosis and the relationship between osteoporosis and hemoglobin level in adult patients with thalassemia in Rajavithi hospital

“…However, patients with thalassemia should be encouraged to have adequate dietary calcium intake, despite the unknown long-term effect on osteoporosis. The prevalence of vitamin D deficiency in this study subjects was much higher (35.3%) compared with the normal Thai population (5.7%) [16]. This study could not demonstrate the importance of vitamin D level on osteoporotic complications of patients with thalassemia intermedia and thalassemia minor.…”

Vitamin D Intake and Serum 25-Hydroxyvitamin D Levels in Korean Adults: Analysis of the 2009 Korea National Health and Nutrition Examination Survey (KNHANES IV-3) Using a Newly Established Vitamin D Database

“…Similar findings were observed in the KNHANES (2008) [13]. In addition, vitamin D status was found to improve with aging in the Thailand National Health Examination Survey (2008–2009) [30]; this was explained by the fact that the elderly had more leisure and outdoor activity time. Therefore, after adjusting for sun exposure time, age, drinking status, smoking status, physical activity (high), and use of vitamin/mineral supplements regarded as a confounding factor for serum 25(OH)D concentrations, vitamin D intake in all participants and those aged <50 years was positively related to serum 25(OH)D concentration in this study.…”

Prevalence of Vitamin D Deficiency Among Perinatally HIV-infected Thai Adolescents Receiving Antiretroviral Therapy

“…8 A report from the Thai National Health Examination Survey in 2008–2009 of 280 healthy people aged above 15 years in Bangkok revealed vitamin D insufficiency in 65% and deficiency in 14%. 9 Although we found a slightly higher rate of vitamin D deficiency in HIV-infected adolescents, but overall rate of vitamin D insufficiency plus deficiency appears to be within a similar range to that seen in HIV-uninfected Thai children and adults. The report in 13 US cities (REACH cohort) of high-risk adolescents 14–18 years of age that found a high rate of vitamin D deficiency (overall 87%), but no differences between HIV-positive and HIV-negative adolescents.…”