Multivariate analysis of a missense variant in CREBRF reveals associations with measures of adiposity in people of Polynesian ancestries.

The minor allele of rs373863828, a missense variant in CREB3 Regulatory Factor, is associated with several cardiometabolic phenotypes in Polynesian peoples. To better understand the variant, we tested the association of rs373863828 with a panel of correlated phenotypes (body mass index [BMI], weight, height, HDL cholesterol, triglycerides, and total cholesterol) using multivariate Bayesian association and network analyses in a Samoa cohort (n = 1632), Aotearoa New Zealand cohort (n = 1419), and combined cohort (n = 2976). An expanded set of phenotypes (adding estimated fat and fat-free mass, abdominal circumference, hip circumference, and abdominal-hip ratio) was tested in the Samoa cohort (n = 1496). In the Samoa cohort, we observed significant associations (log10 Bayes Factor [BF] ≥ 5.0) between rs373863828 and the overall phenotype panel (8.81), weight (8.30), and BMI (6.42). In the Aotearoa New Zealand cohort, we observed suggestive associations (1.5 < log10 BF < 5) between rs373863828 and the overall phenotype panel (4.60), weight (3.27), and BMI (1.80). In the combined cohort, we observed concordant signals with larger log10 BFs. In the Samoa-specific expanded phenotype analyses, we also observed significant associations between rs373863828 and fat mass (5.65), abdominal circumference (5.34), and hip circumference (5.09). Bayesian networks provided evidence for a direct association of rs373863828 with weight and indirect associations with height and BMI.

Association between age at menarche and cardiometabolic risk among Samoan adults.

OBJECTIVES: Recent studies suggest that early menarche may increase cardiometabolic morbidity and mortality. Yet few studies have examined this association in the Pacific Islands, where obesity prevalence is among the highest globally. We sought to examine associations between age at menarche and cardiometabolic risk in Samoa. METHODS: Participants were from the Soifua Manuia study (n = 285, age 32-72 years) conducted in Samoa from 2017 to 2019. Logistic regressions were conducted to estimate odds of obesity, hypertension, diabetes, dyslipidemia, and metabolic syndrome per one-year increase in age at menarche. Linear regressions were conducted to examine associations between age at menarche and continuous measures of adiposity, blood pressure, insulin resistance, and serum lipids. RESULTS: Median age at menarche was 14 years (IQR = 2). After controlling for relevant covariates, each one-year increase in age at menarche was associated with a 15% decrease (OR = 0.85, 95% CI: 0.72-1.01, p = .067) in odds of hypertension, but a 21% increase (OR = 1.21, 95% CI: 1.01-1.45, p = .044) in odds of diabetes and 18% increase (OR = 1.18, 95% CI: 0.98-1.42, p = .081) in odds of high total cholesterol. Each additional year in age at menarche was associated with a 1.60 ± 0.52 kg (p = .002) decrease in lean mass and 1.56 ± 0.51 kg (p = .003) decrease in fat-free mass. CONCLUSIONS: Associations between age at menarche and cardiometabolic risk may be population-specific and are likely influenced by both current and historical nutritional and epidemiological contexts. Prospective studies are needed to clarify the role of childhood adiposity and other early life exposures on age at menarche and subsequent cardiometabolic risk.

O le tagata ma lona aiga, o le tagata ma lona fa'asinomaga (Every person belongs to a family and every family belongs to a person): Development of a parenting framework for adolescent mental wellbeing in American Samoa.

American Samoan adolescents experience a high prevalence of mental health problems, including depression, anxiety, substance use, and suicidal thoughts and behaviors. To complement existing health system efforts, family-based interventions may be a feasible, cost-effective, and relevant opportunity to promote mental health. This community-partnered, qualitative study aimed to: (1) identify potential family-related psychosocial protective factors for adolescent mental health and (2) develop a framework for a parenting program to promote adolescent mental health in American Samoa. Applying the fa'afaletui framework developed for research in Samoan communities, which emphasizes the importance of weaving a range of community member perspectives to reach consensus, semi-structured in-depth interviews with adult key informants (n=28) were conducted between October 2020 and February 2021. Results were validated through five focus groups with Samoan adolescents (n=35) between May and June 2022. Adult participants were sampled for diversity in profession, age, gender, education, and region of residence; adolescent participants were sampled for diversity in gender. Participants were recruited using personal networks and snowball sampling; adolescent participants also responded to Facebook advertising. The semi-structured interviews focused on broad topics including common mental health problems, contributors to mental illness, and potential interventions, among others. Transcripts were coded in duplicate and analyzed using deductive thematic analysis. Themes were collaboratively mapped onto an adapted fonofale model, an existing framework for Pacific Island health research. Six themes described key practices: (1) provide emotional safety and security; (2) provide physical safety and security; (3) encourage sense of self; (4) strengthen intergenerational communication skills; (5) prioritize quality time; and (6) cultivate healthy coping strategies. Participants also expressed the importance of a supportive environment grounded in culture, family and community, and caregiver mental health. These results provide an initial step to identify family-focused factors that promote adolescent mental health in American Samoa and categorize them into a framework to inform intervention development. Drawing on a collaborative and community-partnered process, these findings provide the first evidence-based framework to develop a parenting program to promote adolescent mental wellbeing and resilience in Samoan communities.

Association of rs9939609 in FTO with BMI among Polynesian peoples living in Aotearoa New Zealand and other Pacific nations.

The fat mass and obesity associated (FTO) locus consistently associates with higher body mass index (BMI) across diverse ancestral groups. However, previous small studies of people of Polynesian ancestries have failed to replicate the association. In this study, we used Bayesian meta-analysis to test rs9939609, the most replicated FTO variant, for association with BMI with a large sample (n = 6095) of Aotearoa New Zealanders of Polynesian (Maori and Pacific) ancestry and of Samoan people living in the Independent State of Samoa and in American Samoa. We did not observe statistically significant association within each separate Polynesian subgroup. Bayesian meta-analysis of the Aotearoa New Zealand Polynesian and Samoan samples resulted in a posterior mean effect size estimate of +0.21 kg/m2, with a 95% credible interval [+0.03 kg/m2, +0.39 kg/m2]. While the Bayes Factor (BF) of 0.77 weakly favors the null, the BF = 1.4 Bayesian support interval is [+0.04, +0.20]. These results suggest that rs9939609 in FTO may have a similar effect on mean BMI in people of Polynesian ancestries as previously observed in other ancestral groups.

Validity of anthropometric equation-based estimators of fat mass in Samoan adults.

INTRODUCTION: In 1999, a set of highly accurate Polynesian-specific equations to estimate adult body fat from non-invasive field measures of age, sex, height, and weight (Equation 1), age, sex, height, weight, and bioelectrical impedance analysis (BIA) resistance (Equation 2), and age, sex, height, weight, and the sum of two skinfold thicknesses (Equation 3) were published. The purpose of this study was to evaluate the performance of the equation-based estimators in a sample of Samoan adults recruited 20 years later between 2017 and 2019. METHODS: Age, sex, height, weight, BIA resistance, skinfold thickness, and fat mass as measured using dual energy x-ray absorptiometry (DXA) were available for 432 Samoan adults (mean age 50.9 years, 56% female) seen in 2017/2019. We compared equation-derived fat mass and DXA-derived fat mass using scatterplots and Pearson correlation coefficients. We then updated the equation coefficient estimates in a training set (2/3 of the sample) and evaluated the performance of the updated equations in a testing set (the remaining 1/3 of the sample). RESULTS: Equation-derived fat mass was strongly correlated with DXA-derived fat mass for Equation (1) (r2  = 0.95, n = 432), Equation (2) (r2  = 0.97, n = 425), and Equation (3) (r2  = 0.95, n = 426). Updating the equation coefficient estimates resulted in mostly similar coefficients and nearly identical testing set performance for Equation (1) (r2  = 0.96, n = 153), Equation (2) (r2  = 0.98, n = 150), and Equation (3) (r2  = 0.96, n = 150). CONCLUSIONS: The Polynesian-specific body fat estimation equations remained stable despite changing social and environmental factors and marked increase in obesity prevalence in Samoa.

Preterm birth among Pacific Islanders in the United States and the US-affiliated Pacific Islands: A systematic review and meta-analysis.

OBJECTIVE: To better understand the epidemiology of preterm birth among Pacific Islanders in the United States and the US-Affiliated Pacific Islands. METHODS: Systematic searches of MEDLINE, Embase, CINAHL, PsycINFO, two nonindexed regional journals, and gray literature were conducted and finalized in September 2021. Observational studies published since January 2010 that documented preterm birth outcomes among Pacific Islanders in the United States and the US-Affiliated Pacific Islands were eligible for inclusion. Outcomes of interest included preterm birth prevalence, risk compared with white women, and risk factors for preterm birth among Pacific Islanders. RESULTS: Fourteen of the 3183 screened articles were included in meta-analyses. Random-effects models were used for pooled estimates with 95% confidence intervals. The pooled prevalence of preterm birth among Pacific Islanders was 11.2%, 95% CI: 9.3%-13.6%. Marshallese women had the highest pooled prevalence (20.7%, 95% CI 18.6%-23.0%) among Pacific Islander subgroups. Compared with white women, Pacific Islander women had higher odds of experiencing preterm birth (OR = 1.40, 95% CI: 1.28-1.53). Four risk factors for preterm birth could be explored with the data available: hypertension, diabetes, smoking, and pre-pregnancy body mass index; hypertension and diabetes significantly increased the odds of preterm birth. CONCLUSIONS: Existing literature suggests that United States Pacific Islanders were more likely to experience preterm birth than white women, although the pooled prevalence varied by Pacific Islander subgroup. Data support the need for disaggregation of Pacific Islanders in future research and argue for examination of subgroup-specific outcomes to address perinatal health disparities.

Cross-sectional and prospective associations between household socioeconomic resources, appetite traits, and body size among Samoan infants.

In high-income countries, household socioeconomic resources (as measured by education, occupation, income, and/or household assets) and childhood obesity risk tend to be negatively associated. This association may arise in part because children from households with fewer resources are exposed to obesogenic environments that shape appetite trait development. In contrast, many low- and middle-income countries (LMICs) exhibit a positive association between socioeconomic resources and child body size. There is less evidence from LMIC settings about when during development this association emerges and whether appetite traits play a mediatory role. To explore these questions, we examined cross-sectional and longitudinal associations between socioeconomic resources, appetite traits, and body size among infants in Samoa, an LMIC in Oceania. Data were from the Foafoaga O le Ola prospective birth cohort of 160 mother-infant dyads. Appetite traits were characterized using the Baby and Child Eating Behavior Questionnaires and household socioeconomic resources were quantified using an asset-based measure. While infant body size and household socioeconomic resources were positively associated in both cross-sectional and prospective analyses, we found no evidence that appetite traits mediate this relationship. These results suggest that other aspects of the food environment, such as food security and feeding style, may explain the positive association between socioeconomic resources and body size observed in many LMICs.

Evolutionary history of modern Samoans.

Archaeological studies estimate the initial settlement of Samoa at 2,750 to 2,880 y ago and identify only limited settlement and human modification to the landscape until about 1,000 to 1,500 y ago. At this point, a complex history of migration is thought to have begun with the arrival of people sharing ancestry with Near Oceanic groups (i.e., Austronesian-speaking and Papuan-speaking groups), and was then followed by the arrival of non-Oceanic groups during European colonialism. However, the specifics of this peopling are not entirely clear from the archaeological and anthropological records, and is therefore a focus of continued debate. To shed additional light on the Samoan population history that this peopling reflects, we employ a population genetic approach to analyze 1,197 Samoan high-coverage whole genomes. We identify population splits between the major Samoan islands and detect asymmetrical gene flow to the capital city. We also find an extreme bottleneck until about 1,000 y ago, which is followed by distinct expansions across the islands and subsequent bottlenecks consistent with European colonization. These results provide for an increased understanding of Samoan population history and the dynamics that inform it, and also demonstrate how rapid demographic processes can shape modern genomes.

Prevalence of malnutrition among Samoan children aged 5 to 11 years in 2019-2020.

BACKGROUND: Globally, rapid economic development, urbanisation, and nutrition transitions have led to rising levels of malnutrition in all forms. AIM: The study objective was to document the prevalence of overweight/obesity, underweight, stunting, and anaemia among Samoan children in 2019-2020. SUBJECTS AND METHODS: Children from the Ola Tuputupua'e "Growing Up" in Samoa study at ages 5-11 years with complete physical assessments were included. Overweight/obesity, underweight, and stunting were classified using World Health Organisation Z-scores for body mass index-for-age (BMIZ> +1), weight-for-age (WAZ< -2SD), and height-for-age (HAZ< -2SD), respectively. Anaemia was defined as haemoglobin concentration <11.5 g/dL. Prevalence was compared by child age, sex, and census region of residence (representing urbanicity and exposure to nutrition transition) using Wilcoxon two-sample, Chi-square, or Fisher's exact tests. RESULTS: The prevalence of overweight/obesity, underweight, stunting, and anaemia was 36.2%, 0.5%, 1.6%, and 31.6%, respectively. Overweight/obesity in children was positively associated with age and highly prevalent in periurban and urban regions. While children living in the rural region with the lowest exposure to nutrition transition had the highest prevalence of mild-to-moderate stunting, anaemia prevalence was lower compared to those in the urban region. No sex differences in malnutrition were observed. CONCLUSION: Moderate-to-high levels of overweight/obesity and anaemia call for comprehensive intervention strategies.

Randomized controlled trial to enhance children's sleep, eating, and weight.

BACKGROUND: The present study assessed the efficacy of a behavioral intervention to enhance children's sleep and reduce caloric intake and body mass index (BMI) change. METHODS: Seventy-eight children 8-11 years old who slept 9.5 h/night or less were randomized to the sleep intervention or to no treatment control. The primary outcome was 2-month change in the actigraph-estimated sleep period; changes in reported caloric intake, percent calories from fat, and BMI/BMI z-score (BMIz) were assessed. RESULTS: Children randomized to intervention enhanced their sleep period by 40 ± 7 min/night relative to control (p < 0.001), and were more likely to increase their sleep period by 30 min/night or more (52% versus 15%, p = 0.003). No differences were observed for reported dietary intake or BMI/BMIz. However, in post-hoc analyses collapsing across groups, those who increased sleep by 30 min/night or more had lower BMI (-0.31 kg/m2, p = 0.01) and BMIz (-0.07, p = 0.03) and reported fewer percent calories from fat at 2 months (-2.2%, p = 0.04). CONCLUSIONS: A brief behavioral intervention can enhance children's sleep, but did not result in changes in caloric intake or weight status. Enhancing sleep by 30 min/night or more may be beneficial for weight regulation. IMPACT: A brief behavioral intervention improved children's nocturnal sleep relative to no treatment control. Given the many benefits of a good night's sleep across domains of functioning, findings have significant implications for children's health and wellbeing. There were no differences between groups on eating behaviors or BMI. However, across groups, children who increased their sleep period by at least 30 min/night, reported reduced intake from fat and evidenced lower BMI at 2 months. Thus, a brief intervention can improve sleep and may have potential benefits for weight regulation.

C-reactive protein in adult Samoans: Population variation and physiological correlates.

OBJECTIVES: C-reactive protein (CRP) has been associated with adiposity and cardiometabolic disease risk in many populations but remains remarkably understudied in Pacific Islander populations. Here, we provide the first examination of correlates of CRP in adult Samoans (n = 108, ages 35-55 years) to test the hypotheses that CRP exhibits sex-dependent associations with measures of BMI, adiposity, and cardiometabolic disease risks. METHODS: We analyzed associations between measures of adiposity (total fat mass, visceral fat mass, percent total body fat), body mass index (BMI), cardiometabolic risks, behaviors, demographics, and CRP. Unadjusted analyses of CRP were undertaken using Pearson's pairwise, and Spearman's rank correlations; one-way analysis of variance and Kruskal-Wallis tests assessed variables by CRP quartiles. Adjusted analyses of CRP correlates were examined using generalized linear regression. RESULTS: Serum CRP ranged from 0.08 to 13.3 mg/L (median 1.4 mg/L) and varied significantly by sex t (108) = -2.47, p = .015. CRP was weakly to moderately associated with measures of adiposity and BMI (r and ρ ranged between 0.25 and 0.50, p < .05) and some cardiometabolic markers (including HbA1c, fasting insulin, and insulin resistance). CRP was significantly associated with percent body fat in women and men, adjusting for other variables. CONCLUSIONS: These data are among the first to demonstrate CRP correlates in a sample of adult Samoans. CRP differed by sex and was associated with BMI, adiposity, and some cardiometabolic risk markers. These data align with findings in other populations.

A System for Phenotype Harmonization in the National Heart, Lung, and Blood Institute Trans-Omics for Precision Medicine (TOPMed) Program.

Genotype-phenotype association studies often combine phenotype data from multiple studies to increase statistical power. Harmonization of the data usually requires substantial effort due to heterogeneity in phenotype definitions, study design, data collection procedures, and data-set organization. Here we describe a centralized system for phenotype harmonization that includes input from phenotype domain and study experts, quality control, documentation, reproducible results, and data-sharing mechanisms. This system was developed for the National Heart, Lung, and Blood Institute's Trans-Omics for Precision Medicine (TOPMed) program, which is generating genomic and other -omics data for more than 80 studies with extensive phenotype data. To date, 63 phenotypes have been harmonized across thousands of participants (recruited in 1948-2012) from up to 17 studies per phenotype. Here we discuss challenges in this undertaking and how they were addressed. The harmonized phenotype data and associated documentation have been submitted to National Institutes of Health data repositories for controlled access by the scientific community. We also provide materials to facilitate future harmonization efforts by the community, which include 1) the software code used to generate the 63 harmonized phenotypes, enabling others to reproduce, modify, or extend these harmonizations to additional studies, and 2) the results of labeling thousands of phenotype variables with controlled vocabulary terms.

Genome-wide association studies in Samoans give insight into the genetic architecture of fasting serum lipid levels.

The current understanding of the genetic architecture of lipids has largely come from genome-wide association studies (GWAS). To date, few GWAS have examined the genetic architecture of lipids in Polynesians, and none have in Samoans, whose unique population history, including many population bottlenecks, may provide insight into the biological foundations of variation in lipid levels. Here we performed a GWAS of four fasting serum lipid levels: total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL), and triglycerides (TG) in a sample of 2849 Samoans, with validation genotyping for associations in a replication cohort comprising 1798 Samoans and American Samoans. We identified multiple genome-wide significant associations (P < 5 × 10-8) previously seen in other populations-APOA1 with TG, CETP with HDL, and APOE with TC and LDL-and several suggestive associations (P < 1 × 10-5), including an association of variants downstream of MGAT1 and RAB21 with HDL. However, we observed different association signals for variants near APOE than what has been previously reported in non-Polynesian populations. The association with several known lipid loci combined with the newly identified associations with variants near MGAT1 and RAB21 suggest that while some of the genetic architecture of lipids is shared between Samoans and other populations, part of the genetic architecture may be Polynesian-specific.

Persistence of anaemia among Samoan preschool age children: a longitudinal study.

OBJECTIVE: To characterise the prevalence and persistence of anaemia among Samoan children over a 2-3-year period. DESIGN: Data were from two consecutive waves (2015 and 2017-2018) of the Ola Tuputupua'e 'Growing up' study. Anaemia (Hb < 11·0 or 11·5 g/dl for 2-4 and ≥ 5 years old, respectively) was considered 'transient' when it occurred at only one wave or 'persistent' if it was present at two consecutive waves. Child, maternal and household correlates of anaemia were examined using log-binomial and modified Poisson regressions. SETTING: Eleven Samoan villages. PARTICIPANTS: Mother-child pairs (n 257) recruited in 2015 and reassessed in 2017-2018. RESULTS: Anaemia prevalence was 33·9 % in 2015 and 28·0 % in 2017-2018; 35·6 % of cases identified in 2015 were persistent. Risk of anaemia at only one wave was lower among children who were older in 2015 (age 4 v. 2 years, adjusted relative risk (aRR) = 0·54, (95 % CI 0·35, 0·84), P = 0·007), had older mothers (≥ 40 v. 18-29 years, aRR = 0·61, (95 % CI 0·39, 0·95), P = 0·029) and had higher daily sodium intake (for every 100 mg/d, aRR = 0·97, (95 % CI 0·95, 0·99), P = 0·003) than children with no anaemia. Children whose anaemia persisted were more likely to have had a mother with anaemia (aRR = 2·13, (95 % CI 1·17, 3·89), P = 0·013) and had higher daily dietary iron intake (for every 10 mg/d, aRR = 4·69, (95 % CI 1·33, 16·49), P = 0·016) than those with no anaemia. CONCLUSIONS: Alongside broadly targeted prevention efforts, which are warranted given the moderate-high anaemia prevalence observed, specific attention should be paid to children with risk factors for persistent anaemia. Routine screening of children whose mothers have anaemia should be encouraged.

Barriers and facilitators to pre-exposure prophylaxis uptake among male sex workers in Mexico: an application of the RE-AIM framework.

BACKGROUND: The ImPrEP México demonstration project is the first to distribute free HIV pre-exposure prophylaxis (PrEP) to men who have sex with men (MSM) and transgender women living in Mexico. In Mexico City, MSM who are also male sex workers (MSWs) face a disproportionately high risk of HIV infection. PrEP is highly effective for HIV prevention, yet "real-life" implementation among MSWs is a challenge due to the unique adherence barriers faced by this population. METHODS: This study uses the RE-AIM implementation science framework to characterize the unique barriers to and facilitators of PrEP uptake among MSWs in Mexico City. We conducted 9 in-depth key informant interviews and 2 focus group discussions with MSWs across 5 clinic and community sites. Qualitative data were analyzed using inductive, open coding approaches from grounded theory. We supplemented findings from the primary qualitative analysis with quantitative indicators derived from ImPrEP program records to describe the current Reach of the ImPrEP program among MSWs in Mexico City and the potential for wider PrEP Adoption among other high-risk populations in Mexico. RESULTS: The Reach of the ImPrEP program was 10% of known HIV-negative MSWs in Mexico City. Program Reach was lowest among MSWs who were street-based sex workers, of lower socioeconomic status, migrants from other states and self-identified as heterosexual. Barriers to program Reach included limited PrEP knowledge, HIV-related stigma, and structural barriers; facilitators included in-person program recruitment, patient-centered care, and spread of information through word of mouth among MSWs. Two out of the four eligible institutions had adopted the ImPrEP protocol. Barriers to wider program Adoption included HIV- and sexual identity- related stigma, protocol limitations, and lack of a national policy for PrEP distribution; facilitators of Adoption included existing healthcare infrastructure, sensitized providers, and community support from non-governmental organizations. CONCLUSIONS: Increasing the ImPrEP program's Reach among MSWs will depend on improving PrEP education and addressing HIV-related stigma and access barriers. Future Adoption of the ImPrEP program should build on existing clinical infrastructure and community support. Creation of a national policy for PrEP distribution may improve the Reach and Adoption of PrEP among highest-risk populations in Mexico.

The skeletal maturity of Australian children aged 10-13 years in 2016.

Skeletal maturity can be used as a biological indicator of the tempo of growth in children and adolescents. We present a description of skeletal maturity from a cohort of white Australian children and describe variation in skeletal maturity based on child age. Participants (n = 71; age 10.5-13.9 years) were recruited from the 'Healthy, Active Preschool & Primary Years (HAPPY)' study. Left hand-wrist radiographs were used to determine skeletal maturity using the Tanner-Whitehouse III (TW3) RUS technique. In boys, the mean skeletal maturity offset (bone age - chronological age) was -0.12 ± 0.19 years and 57.9% had delayed skeletal maturity compared to chronological age. Among those with delayed skeletal maturity, the average delay was 0.99 years (range 0.02-2.54 years). In girls, skeletal age was advanced, on average, compared to chronological age by 0.32 ± 0.20 years. Among the 39.4% of girls with delayed skeletal maturity, the average delay was 0.48 years (range: 0.01-2.28). Four children in the sample exhibited a delay in skeletal maturity greater than 2 years. In the context of secular trends towards advanced skeletal maturity observed globally, delayed skeletal maturation in this white, economically privileged cohort are surprising and warrant further exploration.

Feasibility of using infrared thermal imaging to examine brown adipose tissue in infants aged 18 to 25 months.

BACKGROUND: Recent studies in adults indicate that cold-induced temperature change of supraclavicular skin corresponds with brown adipose tissue (BAT) thermogenesis. AIM: This study examined the feasibility of using thermography to assess temperature changes in infants aged 18-25 months after mild cooling. Further, this study sought to evaluate whether cold exposure induces a thermal response suggestive of BAT activity underlying the supraclavicular region. SUBJECTS AND METHODS: Changes in maximum skin temperature at the supraclavicular and interscapular regions were determined using thermal imaging following a mild 5-minute cooling condition (by removal of clothes in a climate-controlled room) in 67 Samoan infants. Temperature changes of the forehead and hand, known BAT-free regions, served as indicators of cooling efficacy. RESULTS: Infants with increased hand and forehead temperatures after cold exposure were excluded from analysis, reducing the effective sample size to 19 infants. On average, forehead (p < 0.001), hand (p < 0.001) and back (0.029) temperatures dropped significantly while supraclavicular temperatures remained constant. Participants with greater decreases in forehead temperature tended to exhibit greater supraclavicular thermogenesis (p = 0.084), suggesting potential BAT activity in this region. CONCLUSIONS: While further work is necessary to develop a reliable cooling condition, this study provides proof-of-concept for non-invasive assessment of BAT activity in infants.

Body size and composition of Samoan toddlers aged 18-25 months in 2019.

BACKGROUND: The "Foafoaga O le Ola (Beginning of Life)" study is a prospective birth cohort of n = 160 Samoan mother-infant dyads established in 2017-2018. A primary study aim is to explore how a missense variant at CREBRF rs373863828 impacts growth in early life, given its association with increased body size but lower risk of diabetes in adult Samoans. Here, we examine body size and composition by genotype among toddlers aged 18.7-24.5 months. METHODS: Height, weight, head circumference, mid-upper-arm circumference, and abdominal circumference, as well as subscapular, triceps, iliac crest and thigh skinfold thickness were measured among 107 toddlers with known rs373863828 genotype; 42 of these toddlers completed dual-energy X-ray absorptiometry (DXA) scans from which body composition (total body less head fat mass, lean mass, bone mass, % fat mass and % fat-free mass) was estimated. RESULTS: After controlling for sex and age, toddlers with at least one copy of the CREBRF minor allele (AA/AG) were 1.31 cm taller (SE = 0.64, p = 0.045) than toddlers with the GG genotype. CONCLUSION: Whether greater linear growth in early childhood could contribute to the metabolically protective effects associated with the CREBRF variant in adulthood should be explored in future studies.

Changing body norms in the context of increasing body size: Samoa in 1995 and 2018.

OBJECTIVE: To understand how body size preferences changed in Samoa between 1995 and 2017 to 2019. METHODS: Data were from adults aged from 31 to 59 years, who participated in two separate cross-sectional studies of obesity and cardiometabolic risk conducted in Samoa in 1995 and 2017 to 2019. Participants nominated line drawings representing their current size, ideal size, the most attractive and healthiest size, and the lower/upper limits of "normal" size. RESULTS: In both sexes, body size preferences and perceived current average body size have increased, yet preference for bodies smaller than one's perceived current size has persisted. Furthermore, the range of body sizes that people considered "normal" has narrowed, suggesting decreased tolerance for extremes of body size. CONCLUSIONS: These findings may have implications for mental and physical health outcomes, inform development of future health initiatives, and contribute to a deeper understanding of how body norms and weight-related public health efforts interface.

A missense variant in CREBRF is associated with taller stature in Samoans.

OBJECTIVES: Studies have demonstrated that rs373863828, a missense variant in CREBRF, is associated with a number of anthropometric traits including body mass index (BMI), obesity, percent body fat, hip circumference, and abdominal circumference. Given the biological relationship between height and adiposity, we hypothesized that the effect of this variant on BMI might be due in part to an association of this variant with height. METHODS: We tested the hypothesis that minor allele of rs373863828 is associated with height in a Samoan population in two adult cohorts and in a separate cohort of children (age 5-18 years old) using linear mixed modeling. RESULTS: We found evidence of a strong relationship between rs373863828 and greater mean height in Samoan adults (0.77 cm greater average height for each copy of the minor allele) with the same direction of effect in Samoan children. CONCLUSIONS: These results suggest that the missense variant rs373863828 in CREBRF, first identified through an association with larger BMI, may be related to an underlying biological mechanism affecting overall body size including stature.