Jatender Mohal

Maternal health in pregnancy and associations with adverse birth outcomes: Evidence from Growing Up in New Zealand

To examine prospectively multiple indicators of pregnancy health and associations with adverse birth outcomes within a large, diverse sample of contemporary women.

Widespread prevalence of a CREBRF variant amongst Māori and Pacific children is associated with weight and height in early childhood

Objective:Investigating a large and ethnically diverse cohort from the Pacific region, we aimed to replicate and extend the recently reported findings that a CREBRF genetic variant is strongly associated with body mass index in Samoans.Methods:A birth cohort of more than six thousand children was utilised. In this study, genotyping of two markers (rs12513649 and rs373863828) was undertaken in Māori, Pacific, European and Asian individuals in the cohort.Results:We report that these CREBRF genetic variants are not confined to Samoans but are prevalent in all other Pacific populations sampled, including Māori. We found that the rs373863828 variant was significantly associated with growth at 4 years of age. On average, we observed allele-specific increases in weight (P=0·004, +455 g, s.e. 0.158), height (P=0·007, +0·70 cm, s.e. 0.26) and waist circumference (P=0·004, +0·70 cm, s.e. 0.24) at 4 years of age. The rs373863828 variant was not associated with birth weight (P=0·129).Conclusions:We replicated the finding that a CREBRF variant is associated with increased body mass. We then built on the original findings by demonstrating the prevalence of the rs12513649 and rs373863828 variants in multiple Pacific population groups and by demonstrating that the rs373863828 variant is associated with growth in early childhood. Pacific population groups experience a disproportionately high burden of obesity, starting in early childhood. This new knowledge offers potential for evidence-based interventions aimed at establishing healthy growth trajectories from the earliest possible age.

A Cross-Cultural Analysis of the Infant Behavior Questionnaire Very Short Form: An Item Response Theory Analysis of Infant Temperament in New Zealand

ABSTRACT The Infant Behavior Questionnaire–Revised Very Short Form (IBQ–R VSF; Putnam, Helbig, Gartstein, Rothbart, & Leerkes, 2014) is a newly published measure of infant temperament with a 3-factor structure. Recently Peterson et al. (2017) suggested that a 5-factor structure (Positive Affectivity/Surgency, Negative Emotionality, Orienting Capacity, Affiliation/Regulation, and Fear) was more parsimonious and showed promising reliability and predictive validity in a large, diverse sample. However, little is known about the 5-factor models precision across the temperament dimensions range and whether it discriminates equally well across ethnicities. A total of 5,567 mothers responded to the IBQ–R VSF in relation to their infants (N = 5,639) between 23 and 52 weeks old. Using item response theory, we conducted a series of 2 parameter logistic item response models and found that 5 IBQ–R VSF temperament dimensions showed a good distribution of estimates across each latent trait range and these estimates centered close to the population mean. The IBQ–R VSF was also similarly precise across 4 ethnic groups (European, Māori, Pacific peoples, and Asians), suggesting that it can be used as comparable measure for infant temperament in a diversity of ethnic groups.

Estimating language skills in Samoan- and Tongan-speaking children growing up in New Zealand

The MacArthur–Bates Communicative Development Inventory (short form) was adapted for Samoan and Tongan speakers in New Zealand. The adaptation process drew upon language samples from Samoan and Tongan parent–child dyads with 20- and 26-month-old children and adult informants. The resulting 100-word language inventories in Samoan and Tongan, plus a single question about word combinations, were then administered to over 600 mothers of 2-year-olds in the Growing Up in New Zealand pre-birth longitudinal cohort study who identified their children as understanding Samoan or Tongan. Most mothers were able to complete the inventories without the help of an interpreter or interviewer. Important demographic correlates of children’s vocabulary and grammar were mothers’ country of birth, education, and deprivation level, and children’s birth order. Mothers’ birthplace was the single best predictor of children’s vocabulary development in Samoan and Tongan, with children of mothers who were born outside New Zealand having higher Samoan and Tongan vocabularies. Clinical implications are discussed, along with future analyses of the language development of these children from the Growing Up cohort.

Housing tenure as a focus for reducing inequalities in the home safety environment: evidence from Growing Up in New Zealand

Objectives: To determine whether specific demographic characteristics are associated with the presence or absence of household safety strategies.