title: Sibling composition during childhood and adult blood pressure among native Amazonians in Bolivia.
abstract: Sibling configuration, including birth order, or the number, age, and sex of siblings is associated with parental resource allocation between children and is thus associated with a person's well-being. Little is known about the association between specific types of siblings and adult health outcomes. Here we test several hypotheses about sibling composition (number of older brothers, older sisters, younger sisters, younger brothers) and adult blood pressure in a foraging-farming society of native Amazonians in Bolivia (Tsimane'). We collected data in 2007 from 374 adults (16-60years of age) from 196 households in 13 villages. Household random-effects multiple regressions were run using systolic (SBP) or diastolic blood pressure (DBP) as outcomes; covariates included the four sibling categories and control variables (e.g., sex, age, education, body mass index [BMI]). Mean SBP and DBP were 114 (SD=14) and 66 (SD=11)mmHg. The prevalence of hypertension was 5.08%. Having an additional younger brother bore a small (3.3-5.9%) positive association with both SBP and DBP, with the effect weakening as people aged. Having an additional younger sister was associated with a small (3.8%) increase in SBP among women, with the magnitude shrinking as people aged. In a large family, the number of younger brothers may exert an impact on an individual's blood pressure.
authors.affiliation: Heller School for Social Policy and Management, Brandeis University, Waltham, MA 02454-9110, USA. wuzengcn@brandeis.edu
authors.forename: Wu
authors.initials: W
authors.lastname: Zeng
authors.forename: Eduardo A
authors.initials: EA
authors.lastname: Undurraga
authors.forename: Colleen
authors.initials: C
authors.lastname: Nyberg
authors.forename: Dan T A
authors.initials: DT
authors.lastname: Eisenberg
authors.forename: Sabita
authors.initials: S
authors.lastname: Parida
authors.forename: Ariela
authors.initials: A
authors.lastname: Zycherman
authors.forename: Oyunbileg
authors.initials: O
authors.lastname: Magvanjav
authors.forename: Victoria
authors.initials: V
authors.lastname: Reyes-García
authors.forename: Susan
authors.initials: S
authors.lastname: Tanner
authors.forename: Ricardo
authors.initials: R
authors.lastname: Godoy
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000884:Anthropology, Cultural; D001722:Birth Order; D001794:Blood Pressure; D001795:Blood Pressure Determination; D001838:Bolivia / Q000453:epidemiology / Q000208:ethnology; D005191:Family Characteristics; D005260:Female; D006306:Health Surveys; D006801:Humans; D006973:Hypertension / Q000453:epidemiology / Q000208:ethnology; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D044382:Population Groups; D012044:Regression Analysis; D012737:Sex Factors; D035781:Siblings / Q000208:ethnology*; D055815:Young Adult