Over the past 5 years, the advent of echocardiographic screening for rheumatic heart disease (RHD) has revealed a higher RHD burden than previously thought. In light of this global experience, the development of new international echocardiographic guidelines that address the full spectrum of the rheumatic disease process is opportune. Systematic differences in the reporting of and diagnostic approach to RHD exist, reflecting differences in local experience and disease patterns. The World Heart Federation echocardiographic criteria for RHD have, therefore, been developed and are formulated on the basis of the best available evidence. Three categories are defined on the basis of assessment by 2D, continuous-wave, and color-Doppler echocardiography: ‘definite RHD’, ‘borderline RHD’, and ‘normal’. Four subcategories of ‘definite RHD’ and three subcategories of ‘borderline RHD’ exist, to reflect the various disease patterns. The morphological features of RHD and the criteria for pathological mitral and aortic regurgitation are also defined. The criteria are modified for those aged over 20 years on the basis of the available evidence. The standardized criteria aim to permit rapid and consistent identification of individuals with RHD without a clear history of acute rheumatic fever and hence allow enrollment into secondary prophylaxis programs. However, important unanswered questions remain about the importance of subclinical disease (borderline or definite RHD on echocardiography without a clinical pathological murmur), and about the practicalities of implementing screening programs. These standardized criteria will help enable new studies to be designed to evaluate the role of echocardiographic screening in RHD control.

Samoans are a unique founder population with a high prevalence of obesity1–3, making them well suited for identifying new genetic contributors to obesity4. We conducted a genome-wide association study (GWAS) in 3,072 Samoans, discovered a variant, rs12513649, strongly associated with body mass index (BMI) (P = 5.3 × 10−14), and replicated the association in 2,102 additional Samoans (P = 1.2 × 10−9). Targeted sequencing identified a strongly associated missense variant, rs373863828 (p.Arg457Gln), in CREBRF (meta P = 1.4 × 10−20). Although this variant is extremely rare in other populations, it is common in Samoans (frequency of 0.259), with an effect size much larger than that of any other known common BMI risk variant (1.36–1.45 kg/m2 per copy of the risk-associated allele). In comparison to wild-type CREBRF, the Arg457Gln variant when overexpressed selectively decreased energy use and increased fat storage in an adipocyte cell model. These data, in combination with evidence of positive selection of the allele encoding p.Arg457Gln, support a ‘thrifty’ variant hypothesis as a factor in human obesity.

Our results in New Zealand Polynesian adults replicate, with very similar effect sizes, the association of the A allele of rs373863828 with higher BMI but lower odds of type 2 diabetes among Samoan adults living in Samoa and American Samoa.

Objective To describe the prevalence of obesity-related noncommunicable diseases (NCDs) and associated risk factors in a sample of Samoan adults studied in 2010 as part of a genome-wide assocation study (GWAS) for obesity related traits. Methods Anthropometric and biochemical data collected from n = 3,475 participants (n = 1,437 male; n = 2,038 female) aged 24.5 to <65 years were used to describe the prevalence of obesity, diabetes, hypertension, and dyslipidemia within the study sample. One way analysis of variance, χ2 tests, and binary logistic regression were used to identify differences in disease and risk factor prevalence by 10-year age group, gender, or by census region of residence. Results Obesity was highly prevalent among the study sample; 64.6% of females and 41.2% of males were obese according to Polynesian cutoffs (BMI ≥ 32 kg/m2). Females were less likely than males to have hypertension (31.7% vs. 36.7%) but equally likely to have diabetes (17.8% vs. 16.4%). With the exception of obesity and low HDL-cholesterol in females only, there were significant differences in the prevalence of all NCDs and associated risk factors by age group, with the oldest age group (55 to <65 years) most affected. In both sexes, residents of the Apia Urban Area were at significantly greater risk of obesity, diabetes, low HDL-cholesterol, and high triglycerides than residents of the more rural Savaii region. Conclusions The phenotypic characteristics of this sample provide evidence of a continuation of previously reported temporal trends toward obesity and its associated disorders. Attention must be paid to the critical NCD situation in Samoa.

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