Validity of self-reported weight, height, and body mass index among university students in Thailand: Implications for population studies of obesity in developing countries

<p>Abstract</p> <p>Background</p> <p>Large-scale epidemiological studies commonly use self-reported weights and heights to determine weight status. Validity of such self-reported data has been assessed primarily in Western populations in developed countries, although its use is widespread in developing countries. We examine the validity of obesity based on self-reported data in an Asian developing country, and derive improved obesity prevalence estimates using the "reduced BMI threshold" method.</p> <p>Methods</p> <p>Self-reported and measured heights and weights were obtained from 741 students attending an open university in Thailand (mean age 34 years). Receiver operator characteristic techniques were applied to derive "reduced BMI thresholds."</p> <p>Results</p> <p>Height was over-reported by a mean of 1.54 cm (SD 2.23) in men and 1.33 cm (1.84) in women. Weight was under-reported by 0.93 kg (3.47) in men and 0.62 kg (2.14) in women. Sensitivity and specificity for determining obesity (Thai BMI threshold 25 kg/m²) using self-reported data were 74.2% and 97.3%, respectively, for men and 71.9% and 100% for women. For men, reducing the BMI threshold to 24.5 kg/m²increased the estimated obesity prevalence based on self-reports from 29.1% to 33.8% (true prevalence was 36.9%). For women, using a BMI threshold of 24.4 kg/m², the improvement was from 12.0% to 15.9% (true prevalence 16.7%).</p> <p>Conclusion</p> <p>Young educated Thais under-report weight and over-report height in ways similar to their counterparts in developed countries. Simple adjustments to BMI thresholds will overcome these reporting biases for estimation of obesity prevalence. Our study suggests that self-reported weights and heights can provide economical and valid measures of weight status in high school-educated populations in developing countries.</p

Factors associated with self-reported number of teeth in a large national cohort of Thai adults

<p>Abstract</p> <p>Background</p> <p>Oral health in later life results from individual's lifelong accumulation of experiences at the personal, community and societal levels. There is little information relating the oral health outcomes to risk factors in Asian middle-income settings such as Thailand today.</p> <p>Methods</p> <p>Data derived from a cohort of 87,134 adults enrolled in Sukhothai Thammathirat Open University who completed self-administered questionnaires in 2005. Cohort members are aged between 15 and 87 years and resided throughout Thailand. This is a large study of self-reported number of teeth among Thai adults. Bivariate and multivariate logistic regressions were used to analyse factors associated with self-reported number of teeth.</p> <p>Results</p> <p>After adjusting for covariates, being female (OR = 1.28), older age (OR = 10.6), having low income (OR = 1.45), having lower education (OR = 1.33), and being a lifetime urban resident (OR = 1.37) were statistically associated (p < 0.0001) with having less than 20 teeth. In addition, daily soft drink consumptions (OR = 1.41), current regular smoking (OR = 1.39), a history of not being breastfed as a child (OR = 1.34), and mother's lack of education (OR = 1.20) contributed significantly to self-reported number of teeth in fully adjusted analyses.</p> <p>Conclusions</p> <p>This study addresses the gap in knowledge on factors associated with self-reported number of teeth. The promotion of healthy childhoods and adult lifestyles are important public health interventions to increase tooth retention in middle and older age.</p