Suggestive Linkage Detected for Blood Pressure Related Traits on 2q and 22q in the Population on the Samoan Islands

Background High blood pressure or hypertension is a major risk factor involved in the development of cardiovascular diseases. We conducted genome-wide variance component linkage analyses to search for loci influencing five blood pressure related traits including the quantitative traits systolic blood pressure (SBP), diastolic blood pressure (DBP) and pulse pressure (PP), the dichotomous trait hypertension (HT) and the bivariate quantitative trait SBP-DBP in families residing in American Samoa and Samoa, as well as in the combined sample from the two polities. We adjusted the traits for a number of environmental covariates such as smoking, alcohol consumption, physical activity and material life style. Results We found suggestive univariate linkage for SBP on chromosome 2q35-q37 (LOD 2.4) and for PP on chromosome 22q13 (LOD 2.2), two chromosomal regions that recently have been associated with SBP and PP, respectively. Conclusion We have detected additional evidence for a recently reported locus associated with SBP on chromosome 2q and a susceptibility locus for PP on chromosome 22q. However, differences observed between the results from our three partly overlapping genetically homogenous study samples from the Samoan islands suggest that additional studies should be performed in order to verify these results

Trends and development of non-communicable diseases and risk factors in Samoa over 24 years

Abstract inserted as part of Final MPH Thesis:Non-Communicable Diseases like diabetes, cardiovascular diseases, cancers and others, have become the major cause of premature death, morbidity and disability in many Pacific countries including Samoa. These are linked by common preventable risk factors like obesity, hypertension, smoking, unhealthy diets and physical inactivity. OBJECTIVES: To determine the trends and development of Non-Communicable diseases and its risk factors in Samoa over the last 24 years using the recently developed diagnostic criteria. RESEARCH DESIGN AND METHODS: This research thesis combines 3 large surveys that were done in 1978, 1991, and 2002, looking at the trends in the prevalence of diabetes, and the prevalence of the NCD risk factors such as blood pressure, obesity, cholesterol and smoking. The 3 survey samples were selected randomly from around similar regions (Urban Upolu, Rural Upolu, and Rural Savaii) of Samoa in 1978, 1991 and 2002, with a total of 5973 individuals (1978 survey = 1467; 1991 survey = 1778; 2002 survey = 2728) available for the thesis analysis. The 1978 and 1991 data sets were secured from Professor P Zimmet, and the 2002 STEPs survey data set was secured from the Samoa Ministry of Health. The 3 surveys methodologies, survey procedures, questionnaires and anthropometric measurements were similar though the diagnostic criteria used to measure obesity slightly differ between the surveys. The blood pressure measurements were similar though the diastolic blood pressure measure in 1978 was higher. The 1978 and 1991 surveys used fasting venous blood sampling to measure fasting plasma glucose, and cholesterol levels at the laboratory. OGTT was also used in 1978 and 1991, but not 2002. The 2002 survey used capillary sampling to measure fasting glucose using a glucometer, and cholesterol level using a cholesterol meter. The combined data was then cleaned, standardized and matched with each survey, to make analysis easier. The recent diagnostic criteria were then applied to all the surveys to diagnose diabetes (1999 WHO Diabetes Criteria), hypertension (WHO 1999, JNC-VII 2003, NHF 1999 Hypertension Criteria), obesity (BMI ≥30 kg/m²), and hypercholesterolaemia. The prevalences using the recent diagnostic criteria were then mapped out.RESULTS: The overall age-standardized prevalence of type 2 diabetes (known or previously unknown) utilizing the current 1999 WHO diagnostic criteria for men and women ≥20 years of age has increased from 5.4% (males 4.8%, females 5.9%) in 1978, to 12.0% (males 10.9%, females 13.5%) in 1991, and to 20.1% (males 17.2%, females 22.2%) in 2002. Among the individuals with diabetes in the 3 surveys, more than 60% had previously undiagnosed diabetes. Compared with the 1978 survey, the diabetes prevalence in 2002 represents a 4-fold increase over the 24 year period. This has occurred along with increasing obesity, urbanization and modernization, aging, cultural changes, and changes in physical activity. There is a high prevalence of non-communicable disease risk factors. The age-standardized prevalence of hypertension defined by the WHO 1999 and JNC-VII 2003 criteria was 47.2% in 1978, 22.5% in 1991, and 24.0% in 2002. The high prevalence of hypertension in 1978 was due to the method used for recording diastolic blood pressure. Hypertension was more common in the urban regions than rural regions in 1978 and 1991 while in 2002, there was no statistical difference between the rates of hypertension between the different regions due to the rise in the prevalence rate of hypertension in rural regions. There is a high prevalence of overweight and obesity in Samoa. Using the WHO classification for BMI, there was an increase in obesity (BMI ≥ 30kg/m²) prevalence in Samoa in the last decade, increasing steeply from 34.9% in 1978 to 51.3% in 1991, and slowing down to an increase to 57.4% in 2002. The prevalence of obesity is significantly higher in females compared with their male counterparts. The overweight prevalence (BMI 25-29.9kg/m²) was 34% in 1978, 31% in 1991 and 29% in 2002. The prevalence of obesity has increased by 65% from 1978 to 2002 with an increase of 47% from 1978 to 1991, and 12% from 1991 to 2002. Prevalence of obesity is increasing with age and is more of a problem in women than men. It is higher in the urban regions but there has been a faster rise in obesity prevalence in rural regions from 1978 to 2002 as the rural regions become urbanized. The prevalence of hypercholesterolaemia (total cholesterol ≥ 5.2 mmol/l) was 30.5% in 1978, and this increased to 51.1% in 1991. There was a marked decline of hypercholesterolaemia in 2002 (14.4%), which may be due to differences in the method of measurement. Although smoking prevalence remains high in Samoa it declined significantly from 42.4% 1978 to 35.3% 1991 but remained essentially steady at 38% in 2002. There was a significant gender difference in smoking with about 60% of men and 20% of women smoking regularly. CONCLUSION: Samoa is experiencing an increasing problem with Non-Communicable diseases like diabetes and some of its risk factors. Diabetes prevalence has dramatically increased by 4-fold in the last 24 years. The prevalence of hypertension has stabilized around 23% though there was a decrease from 1978. The prevalence of obesity has also increased. Smoking prevalence has slightly increased from 1991 to 2002 with a significant number of the population smoking. Hypercholesterolaemia is more common in 1991 with an apparent decrease in 2002. These findings have important implications for public health efforts and policy developments to contain the epidemic of Non-Communicable diseases in Samoa

The influence of socioeconomic factors on cardiovascular disease risk factors in the context of economic development in the Samoan archipelago

Early in economic development there are positive associations between socioeconomic status (SES) and cardiovascular disease (CVD) risk factors, and in the most developed market economy societies there are negative associations. The purpose of this report is to describe cross-sectional and longitudinal associations between indicators of SES and CVD risk factors in a genetically homogenous population of Samoans at different levels of economic development. At baseline 1289 participants 25-58 yrs, and at 4-year follow-up, 963 participants were studied in less economically developed Samoa and in more developed American Samoa. SES was assessed by education, occupation, and material lifestyle at baseline. The CVD risk factors, obesity, type-2 diabetes and hypertension were measured at baseline and 4-year follow-up, and an index of any incident CVD risk factor at follow-up was calculated. Sex and location (Samoa and American Samoa) specific multivariable logistic regression models were used to test for relationships between SES and CVD risk factors at baseline after adjustment for age and the other SES indicators. In addition an ordinal SES index was constructed for each individual based on all three SES indicators, and used in a multivariable model to estimate the predicted probability of CVD risk factors across the SES index for the two locations. In both the models using specific SES measures and CVD risk factor outcomes, and the models using the ordinal SES index and predicted probabilities of CVD risk factors, we detected a pattern of high SES associated with: (1) elevated odds of CVD risk factors in less developed Samoa, and (2) decreased odds of CVD risk factors in more developed American Samoa. We conclude that the pattern of inverse associations between SES and CVD risk factors in Samoa and direct associations in American Samoa is attributable to the heterogeneity across the Samoas in specific exposures to social processes of economic development and the natural history of individual CVD risk factors. The findings suggest that interventions on non-communicable diseases in the Samoas must be devised based on the level of economic development, the socio-economic context of risk factor exposures, and individual characteristics such as age, sex and education level.Polynesia Socio-economic factors Cardiovascular disease risk factors Economic development Obesity Type 2 diabetes

Identifying patient preferences for diabetes care: A protocol for implementing a discrete choice experiment in Samoa.

In Samoa, adult Type 2 diabetes prevalence has increased within the past 30 years. Patient preferences for care are factors known to influence treatment adherence and are associated with reduced disease progression and severity. However, patient preferences for diabetes care, generally, are understudied, and other patient-centered factors such as willingness-to-pay (WTP) for diabetes treatment have never been explored in this setting. Discrete Choice Experiments (DCE) are useful tools to elicit preferences and WTP for healthcare. DCEs present patients with hypothetical scenarios composed of a series of multi-alternative choice profiles made up of attributes and levels. Patients choose a profile based on which attributes and levels may be preferable for them, thereby quantifying and identifying locally relevant patient-centered preferences. This paper presents the protocol for the design, piloting, and implementation of a DCE identifying patient preferences for diabetes care, in Samoa. Using an exploratory sequential mixed methods design, formative data from a literature review and semi-structured interviews with n = 20 Samoan adults living with Type 2 diabetes was used to design a Best-Best DCE instrument. Experimental design procedures were used to reduce the number of choice-sets and balance the instrument. Following pilot testing, the DCE is being administered to n = 450 Samoan adults living with diabetes, along with associated questionnaires, and anthropometrics. Subsequently, we will also be assessing longitudinally how preferences for care change over time. Data will be analyzed using progressive mixed Rank Order Logit models. The results will identify which diabetes care attributes are important to patients (p < 0.05), examine associations between participant characteristics and preference, illuminate the trade-offs participants are willing to make, and the probability of uptake, and WTP for specific attributes and levels. The results from this study will provide integral data useful for designing and adapting efficacious diabetes intervention and treatment approaches in this setting

Assessing the impact of high blood pressure referrals on hypertension awareness and management, BMI, and blood pressure values in adult Samoans 2010–2019

The Samoan population has experienced rapid increases in the prevalence of non-communicable diseases (NCDs) and NCD risk factors over the last 30 years. However, understanding how increased awareness and treatment of these conditions in reducing disease burden remains understudied. Using data from a longitudinal study (2010–2019) of cardiometabolic health among Samoan adults, we assess the impact of a referral for elevated blood pressure (BP) on changes in BP, physician’s diagnoses of hypertension and medication use, body mass index (BMI), and other risk factors for elevated BP. Analyses compared adult Samoans (n = 328) who in 2010 either (1) received a referral for elevated BP (BP ≥ 140/90 mmHg) or (2) had measured BP indicative of pre-hypertension (BP ≥ 120/80 mmHg) but were not referred. Data were analysed using linear and logistic regression, paired T- and McNemar’s tests, and Wilcoxon Rank Sum assessments. Referrals in 2010 significantly increased the odds of reporting a physician’s diagnosis of hypertension (OR 2.16; 1.18, 3.95) and hypertension medication use (OR 3.52; 1.86, 6.73) in 2018; however, referrals, medication use, and diagnoses were not associated with BP values or reduced odds of having elevated BP. Despite the referral having positive effects on hypertension-related health care, our results demonstrate that other factors are influencing effective BP/hypertension control. We advocate for greater engagement of health researchers with local health sector actors to improve the probability that researcher-provided health referrals will result in long-term health improvements

Type 2 Diabetes and Three Calpain-10 Gene Polymorphisms in Samoans: No Evidence of Association

Although genomewide scans have identified several potential chromosomal susceptibility regions in several human populations, finding a causative gene for type 2 diabetes has remained elusive. Others have reported a novel gene, calpain-10 (CAPN10), located in a previously identified region on chromosome 2q37.3, as a putative susceptibility gene for type 2 diabetes. Three single-nucleotide polymorphisms (SNPs) (UCSNP43, UCSNP19, and UCSNP63) were shown to be involved in increased risk of the disease among Mexican Americans. We have tested the association of these three SNPs with type 2 diabetes among the Samoans of Polynesia, who have a very high prevalence of the disease. In the U.S. territory of American Samoa, prevalence is 25% and 15% in men and women, respectively, whereas, in the independent nation of Samoa, prevalence is 3% and 5% in men and women, respectively. In our study sample, which consisted of 172 unrelated affected case subjects and 96 control subjects, we failed to detect any association between case subjects and control subjects in allele frequencies, haplotype frequencies, or haplotype combinations of UCSNP43, -19, and -63. Also, our data showed no evidence of linkage, among 201 affected sib pairs, in the region of chromosome 2 that contains these SNPs. Three plausible scenarios could explain these observations. (1) CAPN10 is a susceptibility gene only in particular ethnic groups; (2) our study lacks power to detect the effects of CAPN10 polymorphisms (but our sample size is comparable to that of earlier reports); or (3) the underlying biological mechanism is too complex and requires further research

2023 World Heart Federation guidelines for the echocardiographic diagnosis of rheumatic heart disease

© Springer Nature Limited 2023, corrected publication 2024.Rheumatic heart disease (RHD) is an important and preventable cause of morbidity and mortality among children and young adults in low-income and middle-income countries, as well as among certain at-risk populations living in high-income countries. The 2012 World Heart Federation echocardiographic criteria provided a standardized approach for the identification of RHD and facilitated an improvement in early case detection. The 2012 criteria were used to define disease burden in numerous epidemiological studies, but researchers and clinicians have since highlighted limitations that have prompted a revision. In this updated version of the guidelines, we incorporate evidence from a scoping review, an expert panel and end-user feedback and present an approach for active case finding for RHD, including the use of screening and confirmatory criteria. These guidelines also introduce a new stage-based classification for RHD to identify the risk of disease progression. They describe the latest evidence and recommendations on population-based echocardiographic active case finding and risk stratification. Secondary antibiotic prophylaxis, echocardiography equipment and task sharing for RHD active case finding are also discussed. These World Heart Federation 2023 guidelines provide a concise and updated resource for clinical and research applications in RHD-endemic regions.info:eu-repo/semantics/publishedVersio