Phongtape Wiwatanadate

Acute effects of air pollution on peak expiratory flow rates and symptoms among asthmatic patients in Chiang Mai, Thailand

The open burnings and forest fires have been recognized as the major sources of severe air pollution in the upper north of Thailand; however, there have been no clear evidences to show the associations between the air pollution and health effects in the area. We assessed the effects of air pollutants on the peak expiratory flow rates (PEFR) and symptoms in asthmatics. A cohort of 121 asthmatics was followed daily, for 306 days, for their PEFR and asthma symptoms. The daily air pollutants, including particulate matter with aerodynamic diameter <2.5 μm, particulate matter with aerodynamic diameter <10 μm (PM(10)), carbon monoxide, ozone, nitrogen dioxide (NO(2)), and sulfur dioxide (SO(2)), and the meteorological parameters, including pressure, temperature, relative humidity, rain quantity, and sunshine duration, were monitored. The PEFRs were fitted with general linear mixed models. The asthma symptoms were analyzed with the generalized estimating equations. There were positive associations of NO(2) with morning PEFR, with a coefficient of 0.06 [95% confidence interval (CI), 0.00-0.12]; of SO(2) with evening PEFR [with a range of coefficients of 0.88-1.00 (95% CI, 0.31-1.54)] and daily average PEFR [with a coefficient of 0.47 (95% CI, 0.00-0.94)]; of PM(10) with evening PEFR, with a coefficient of 0.02 (95% CI, 0.00-0.04). There was also negative association of PM(10) with ΔPEFR, with a coefficient of -0.01 (95% CI, -0.01 to -0.00). No pollutants were related to asthma symptoms. More studies are needed, particularly at low dose in adult asthmatics, to validate our findings.

Stigma, Social Support, and Treatment Adherence Among HIV-Positive Patients in Chiang Mai, Thailand

Our study assessed the influence of HIV-related stigma on treatment adherence among people living with HIV in Chiang Mai, Thailand, and whether social support had a moderating effect on this relationship. We recruited 128 patients living with HIV from Sansai Hospital, a community hospital in Chiang Mai, Thailand, and collected data through structured interviews. All forms of HIV-related stigma considered in this study (personalized experience, disclosure, negative self-image, and public attitudes) were negatively correlated with adherence to anti-retroviral regimens. Multiple linear regression indicated that total HIV-related stigma was more predictive of treatment adherence than any individual stigma type, after adjusting for socio-demographic and health characteristics. Tests of interaction showed that social support did not appear to moderate the association between HIV stigma and treatment adherence. Our findings suggest that community and government efforts to improve public perceptions about people living with HIV might promote treatment adherence behaviors among HIV-positive patients.

Air pollution-related peak expiratory flow rates among asthmatic children in Chiang Mai, Thailand

The severity of air pollution in northern Thailand has long been recognized; in spite of that there have been no epidemiological studies regarding the associations between the air pollution and health effects in the area. The authors followed a cohort of 31 asthmatic children (4–11 years of age) residing in Muang district, Chiang Mai, Thailand, from 29 August 2005 to 30 June 2006, for 306 days. The daily air pollutants, including particulate matter with aerodynamic diameter < 2.5 μm, particulate matter with aerodynamic diameter < 10 μm, carbon monoxide, ozone (O3), nitrogen dioxide, and sulfur dioxide (SO2), and the meteorological parameters, including pressure, temperature, relative humidity, rain quantity, and sunshine duration, were recorded. The peak expiratory flow rates (PEFRs) were fitted with pollutants and meteorological covariates using general linear mixed models to account for random effects and autocorrelation. The authors found that there were inverse associations of SO2 and evening PEFR, with a coefficient of -2.12 (95% confidence interval (CI) = -3.22 to -0.28); of SO2 and daily percent deviation of PEFR, with a coefficient of -0.73 (95% CI = -1.33 to -0.12); and of O3 combining with SO2 and daily average PEFR, with a coefficient of -0.16 (95% CI = -0.31 to -0.00) and -1.60 (95% CI = -3.10 to -0.11), respectively. The associations of O3 and SO2 with PEFR were found even when SO2 concentrations never exceeded the standard level.

Association of fluoride in water for consumption and chronic pain of body parts in residents of San Kamphaeng district, Chiang Mai, Thailand.

Objective  To assess the dose response of fluoride exposure from water and chronic pain.

Pesticide use among farmers in Mae Tha, Thailand: Perceptions of health risk as a determinant of practice

Human behavior can change through external influence. However, internal influences, such as individual perceptions, are more powerful in triggering long-term action, ultimately allowing for substantial changes in behavioral patterns. Applying the aforementioned idea to farming practices, the following study seeks to understand the possible association between risk perception and agro-chemical use patterns between conventional and organic farms, the former using chemical pesticides and fertilizers.

Recommended Rice Intake Levels Based on Average Daily Dose and Urinary Excretion of Cadmium in a Cadmium-Contaminated Area of Northwestern Thailand

This study was performed to investigate the dose-response relationship between average daily cadmium dose (ADCD) from rice and the occurrence of urinary cadmium (U-Cd) in individuals eating that rice. This was a retrospective cohort designed to compare populations from two areas with different levels of cadmium contamination. Five-hundred and sixty-seven participants aged 18 years or older were interviewed to estimate their rice intake, and were assessed for U-Cd. The sources of consumed rice were sampled for cadmium measurement, from which the ADCD was estimated. Binary logistic regression was used to examine the association between ADCD and U-Cd (cut-off point at 2 μg/g creatinine), and a correlation between them was established. The lowest estimate was ADCD = 0.5 μg/kg bw/day [odds ratio (OR) = 1.71; with a 95% confidence interval (CI) 1.02–2.87]. For comparison, the relationship in the contaminated area is expressed by ADCD = 0.7 μg/kg bw/day, OR = 1.84; [95 % CI, 1.06–3.19], while no relationship was found in the non-contaminated area, meaning that the highest level at which this relationship does not exist is ADCD = 0.6 μg/kg bw/day [95% CI, 0.99–2.95]. Rice, as a main staple food, is the most likely source of dietary cadmium. Abstaining from or limiting rice consumption, therefore, will increase the likelihood of maintaining U-Cd within the normal range. As the recommended maximum ADCD is not to exceed 0.6 μg/kg bw/day, the consumption of rice grown in cadmium-contaminated areas should not be more than 246.8 g/day. However, the exclusion of many edible plants grown in the contaminated area from the analysis might result in an estimated ADCD that does not reflect the true level of cadmium exposure among local people.