Dinusha K. Bandara

In the 21st Century, what is an acceptable response rate?

Response rates for epidemiologic studies have dropped dramatically over the past several decades, from rates of more than 90% in the 1950s to those that often struggle to reach 70%, and frequently are much lower. The obvious question for editors and reviewers of scientific papers is: “what is an acceptable response rate in the 21 Century?” This paper provides a discussion of this important and timely question. It suggests that there should be an expectation that response rates should be routinely, and accurately, reported in population-based studies, but argues that response rate alone may not be sufficient evidence to judge study quality and/or validity. It suggests that, in addition to reporting the response rates, requiring authors to disclose any known details about their non-participants, attempts to improve participation, and the denominators used to calculate response rates should assist editors and reviewers to assess the validity and utility of study findings more accurately and make decisions about their relevance for their readers.

Cohort Profile: Growing Up in New Zealand

Centre for Longitudinal Research – He Ara ki Mua, University of Auckland, Auckland, New Zealand, Growing Up in New Zealand, University of Auckland, Auckland, New Zealand, School of Medicine, University of Auckland, Auckland, New Zealand, Starship Children’s Hospital, Auckland District Health Board, Auckland, New Zealand, School of Population Health, University of Auckland, Auckland, New Zealand, Department of Public Health, School of Medicine and Health Sciences, University of Otago, Wellington, New Zealand, Office of the Deputy Vice-Chancellor (Māori), Massey University, Wellington, New Zealand, Bioinformatics Institute, University of Auckland, Auckland, New Zealand, Ministry of Pacific Island Affairs, Auckland Office, Auckland, New Zealand, Department of Psychology, University of Auckland, Auckland, New Zealand, Roy McKenzie Centre for the Study of Families, Victoria University, Wellington, New Zealand, Department of Psychology, University of Otago, Dunedin, New Zealand and School of Medical Sciences, University of Auckland, Auckland, New Zealand

Adherence to nutritional guidelines in pregnancy: evidence from the Growing Up in New Zealand birth cohort study.

OBJECTIVE To determine adherence to nutritional guidelines by pregnant women in New Zealand and maternal characteristics associated with adherence. DESIGN A cohort of the pregnant women enrolled into New Zealands new birth cohort study, Growing Up in New Zealand. SETTING Women residing within a North Island region of New Zealand, where one-third of the national population lives. SUBJECTS Pregnant women (n 5664) were interviewed during 2009-2010. An FFQ was administered during the face-to-face interview. RESULTS The recommended daily number of servings of vegetables and fruit (≥6) were met by 25 % of the women; of breads and cereals (≥6) by 26 %; of milk and milk products (≥3) by 58 %; and of lean meat, meat alternatives and eggs (≥2) by 21 %. One in four women did not meet the recommendations for any food group. Only 3 % met all four food group recommendations. Although adherence to recommendation for the vegetables/fruit group did not vary by ethnicity (P=0·38), it did vary for the breads/cereals, milk/milk products and meat/eggs groups (all P<0·001). Adherence to recommendations for the vegetables/fruit group was higher among older women (P=0·001); for the breads/cereals group was higher for women with previous children (P<0·001) and from lower-income households (P<0·001); and for the meat/eggs group was higher for women with previous children (P=0·003) and from lower-income households (P=0·004). CONCLUSIONS Most pregnant women in New Zealand do not adhere to nutritional guidelines in pregnancy, with only 3 % meeting the recommendations for all four food groups. Adherence varies more so with ethnicity than with other sociodemographic characteristics.

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.

Early engagement with a Lead Maternity Carer: Results from Growing Up in New Zealand

Timely engagement in antenatal care improves maternal and child health outcomes and is an important element of healthcare performance measurement.

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.

Dietary Patterns in Pregnancy in New Zealand—Influence of Maternal Socio-Demographic, Health and Lifestyle Factors

Exploration of dietary pattern associations within a multi-ethnic society context has been limited. We aimed to describe dietary patterns of 5664 pregnant women from the Growing Up in New Zealand study, and investigate associations between these patterns and maternal socio-demographic, place of birth, health and lifestyle factors. Participants completed a food frequency questionnaire prior to the birth of their child. Principal components analysis was used to extract dietary patterns and multivariable analyses used to determine associations. Four dietary components were extracted. Higher scores on, ‘Junk’ and ‘Traditional/White bread’, were associated with decreasing age, lower educational levels, being of Pacific or Māori ethnicity and smoking. Higher scores on, ‘Health conscious’ and ‘Fusion/Protein’, were associated with increasing age, better self-rated health, lower pre-pregnancy body mass index (BMI) and not smoking. Higher scores on ‘Junk’ and ‘Health conscious’ were associated with being born in New Zealand (NZ), whereas higher scores on ‘Fusion/Protein’ was associated with being born outside NZ and being of non-European ethnicity, particularly Asian. High scores on the ‘Health conscious’ dietary pattern showed the highest odds of adherence to the pregnancy dietary guidelines. In this cohort of pregnant women different dietary patterns were associated with migration, ethnicity, socio-demographic characteristics, health behaviors and adherence to dietary guidelines.

Provider engagement and choice in the Lead Maternity Carer System: Evidence from Growing Up in New Zealand.

New Zealand (NZ) has a unique choice‐based model of maternity care.

Agreement between Future Parents on Infant Feeding Intentions and Its Association with Breastfeeding Duration: Results from the Growing Up in New Zealand Cohort Study

Maternal intentions are believed to have the strongest influence on infant feeding. However, what has rarely been studied, are the associations of maternal and partner intentions, and the influence these factors have on infant feeding. Our objective was to describe breastfeeding intentions of pregnant women and their partners, agreement about these intentions, and whether this agreement is associated with breastfeeding initiation and duration. This study was completed within the Growing Up in New Zealand study. Agreement between mothers and partners on intended initial infant feeding method was fair (κ = 0.21, 95% confidence interval (CI) 0.17–0.25) as was intended breastfeeding duration (κ = 0.25, 95% CI 0.22–0.28). Infants whose parents agreed antenatally on breastfeeding only were more likely to have been breastfed for >6 months, after adjustment for maternal (odds ratio (OR) = 6.3, 95% CI 3.9–10.2) and partner demographics (OR = 5.7, 95% CI 3.6–9.2). Likewise, infants whose parents agreed antenatally to breastfeed for >6 months were more likely to have been breastfed for >6 months, after adjustment for maternal (OR = 4.9, 95% CI 3.9–6.2) and partner demographics (OR = 5.0, 95% CI 4.0–6.3). Interventions that promote breastfeeding to both mothers and partners which enable parents to reach agreement about intended feeding methods have the potential to increase both breastfeeding initiation and duration.

Caring for our infants: parents’ antenatal childcare intentions and nine-month reality

Abstract Infants are increasingly cared for by adults other than their parents. Here we describe non-parental infant care within a diverse cohort; and investigate the relationship between parents’ antenatal intentions and actual infant care. 6822 New Zealand women were recruited during pregnancy and asked about their intentions for childcare. Non-parental care was assessed when infants were nine months old: 1717 (25%) of the 6853 cohort children were receiving more than 8 h per week of regular non-parental care. In comparison with infants of European mothers, infants of Asian or Pacific mothers were more likely to be cared for by extended family; and infants of Māori mothers were more likely to receive centre-based care. Infants from families with lower household incomes, living in more deprived areas were more likely to be cared for by family. When their infants were nine months old, mothers from low- to medium-income households were less likely to be using the type of non-parental care they had intended antenatally, and the same was true when their children were aged 2 years.