Testing the thrifty gene hypothesis: the Gly482Ser variant in PPARGC1A is associated with BMI in Tongans

<p>Abstract</p> <p>Background</p> <p>The thrifty gene hypothesis posits that, in populations that experienced periods of feast and famine, natural selection favoured individuals carrying thrifty alleles that promote the storage of fat and energy. Polynesians likely experienced long periods of cold stress and starvation during their settlement of the Pacific and today have high rates of obesity and type 2 diabetes (T2DM), possibly due to past positive selection for thrifty alleles. Alternatively, T2DM risk alleles may simply have drifted to high frequency in Polynesians. To identify thrifty alleles in Polynesians, we previously examined evidence of positive selection on T2DM-associated SNPs and identified a T2DM risk allele at unusually high frequency in Polynesians. We suggested that the risk allele of the Gly482Ser variant in the <it>PPARGC1A </it>gene was driven to high frequency in Polynesians by positive selection and therefore possibly represented a thrifty allele in the Pacific.</p> <p>Methods</p> <p>Here we examine whether <it>PPARGC1A </it>is a thrifty gene in Pacific populations by testing for an association between Gly482Ser genotypes and BMI in two Pacific populations (Maori and Tongans) and by evaluating the frequency of the risk allele of the Gly482Ser variant in a sample of worldwide populations.</p> <p>Results</p> <p>We find that the Gly482Ser variant is associated with BMI in Tongans but not in Maori. In a sample of 58 populations worldwide, we also show that the 482Ser risk allele reaches its highest frequency in the Pacific.</p> <p>Conclusion</p> <p>The association between Gly482Ser genotypes and BMI in Tongans together with the worldwide frequency distribution of the Gly482Ser risk allele suggests that <it>PPARGC1A </it>remains a candidate thrifty gene in Pacific populations.</p

Harrison boiler. Safe. An essay on the steam-boiler. Read before the Franklin institue, Philadelphia, January 16, 1867.

96 p. fold. front., illus. 24 cm

Obesity among school children in a province of southern Thailand and its association with socioeconomic status

The association of nutrition status of children aged 7–12 years (n=663) with socioeconomic factors in a province of southern Thailand in 1995 was investigated. Three type of schools were surveyed: a school with a higher educational standard (elite school) in the municipality of the province, a school with many children from low-income families (low-income school) in the same municipality, and five ordinary schools in rural areas of the province (district schools). The proportions of obese children were 22.1%, 5.8% and 2.7%, respectively for the three type of schools, when obesity was defined as weight to height of over 120% of the median of children in Bangkok. The risk ratios and 95% confidence intervals for obesity in the elite and the low-income schools were 5.0 (3.5–7.2) and 1.9 (0.8–4.8), respectively, taking the district schools as a reference. Our research suggested that the high prevalence of obesity among elite-school children could be related to the comparatively high socioeconomic status of the children’s families. It also shows that the children in the province studied were as a whole considerably leaner than children in the big cities of Thailand. These results imply a need for appropriate interventions which cannot only prevent obesity, but also improve the malnutrition of school children in the rural provinces of southern Thailand