Polly E. Atatoa Carr

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

'Growing up in New Zealand' cohort alignment with all New Zealand births

Objective: To compare the birth characteristics of the Growing Up in New Zealand cohort with those of all New Zealand (NZ) births over a similar time period, and to describe cohort alignment to current NZ births.

How do you Recruit and Retain a Prebirth Cohort? Lessons Learnt from Growing Up in New Zealand

Growing Up in New Zealand, a longitudinal study following nearly 7,000 children, has faced some unique challenges in identifying, enrolling, and retaining a large and diverse antenatal cohort. Identification of a study region with population demographics that enabled enrollment of an appropriately diverse sample was required as was intensive community and participant engagement in order to promote the study. Complementary methods used included direct engagement with prospective participants and the community and indirect engagement via media. Thus far, retention rates above 95% have been achieved by maintaining a multimethod approach that includes valuing participants and building trusting relationships, strong brand recognition, community engagement, maintenance of participant contact and location records, ensuring high-quality interactions between the participants and the study, pretesting measures and methods prior to the main cohort, and using participant feedback to inform the measures and methods used in future waves of data collection.

Depression symptoms during pregnancy: Evidence from Growing Up in New Zealand

BACKGROUND Depression during pregnancy has significant implications for pregnancy outcomes and maternal and child health. There is a need to identify which family, physical and mental health factors are associated with depression during pregnancy. METHODS An ethnically and socioeconomically diverse sample of 5664 pregnant women living in New Zealand completed a face-to-face interview during the third trimester. Antenatal depression (AD) symptoms were assessed using the Edinburgh Postnatal Depression Scale (EPDS). Maternal demographic, physical and mental health, and family and relationship characteristics were measured. The association between symptoms of AD and maternal characteristics was determined using multiple logistic regression. RESULTS 11.9% of the participating women had EPDS scores (13+) that indicated probable AD. When considering sociodemographic predictors of AD symptoms, we found that women from non-European ethnicities, specifically Pacific Islander, Asian and other, were more likely to suffer from AD symptoms. Greater perceived stress during pregnancy and a diagnosis of anxiety both before and during pregnancy were also associated with greater odds of having AD according to the EPDS. LIMITATIONS The women were in their third trimester of pregnancy at the interview. Therefore, we cannot discount the possibility of recall bias for questions relating to pre-pregnancy status or early-pregnancy behaviours. CONCLUSIONS AD is prevalent amongst New Zealand women. Ethnicity, perceived stress and anxiety are particularly associated with a greater likelihood of depression during pregnancy. Further attention to supporting maternal mental health status in the antenatal period is required.

Structural Conservation, Variability, and Immunogenicity of the T6 Backbone Pilin of Serotype M6 Streptococcus pyogenes

ABSTRACT Group A streptococcus (GAS; Streptococcus pyogenes) is a Gram-positive human pathogen that causes a broad range of diseases ranging from acute pharyngitis to the poststreptococcal sequelae of acute rheumatic fever. GAS pili are highly diverse, long protein polymers that extend from the cell surface. They have multiple roles in infection and are promising candidates for vaccine development. This study describes the structure of the T6 backbone pilin (BP; Lancefield T-antigen) from the important M6 serotype. The structure reveals a modular arrangement of three tandem immunoglobulin-like domains, two with internal isopeptide bonds. The T6 pilin lysine, essential for polymerization, is located in a novel VAKS motif that is structurally homologous to the canonical YPKN pilin lysine in other three- and four-domain Gram-positive pilins. The T6 structure also highlights a conserved pilin core whose surface is decorated with highly variable loops and extensions. Comparison to other Gram-positive BPs shows that many of the largest variable extensions are found in conserved locations. Studies with sera from patients diagnosed with GAS-associated acute rheumatic fever showed that each of the three T6 domains, and the largest of the variable extensions (V8), are targeted by IgG during infection in vivo. Although the GAS BP show large variations in size and sequence, the modular nature of the pilus proteins revealed by the T6 structure may aid the future design of a pilus-based vaccine.

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.

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.

Serological Evidence of Immune Priming by Group A Streptococci in Patients with Acute Rheumatic Fever.

Acute rheumatic fever (ARF) is an autoimmune response to Group A Streptococcus (GAS) infection. Repeated GAS exposures are proposed to ‘prime’ the immune system for autoimmunity. This notion of immune-priming by multiple GAS infections was first postulated in the 1960s, but direct experimental evidence to support the hypothesis has been lacking. Here, we present novel methodology, based on antibody responses to GAS T-antigens, that enables previous GAS exposures to be mapped in patient sera. T-antigens are surface expressed, type specific antigens and GAS strains fall into 18 major clades or T-types. A panel of recombinant T-antigens was generated and immunoassays were performed in parallel with serum depletion experiments allowing type-specific T-antigen antibodies to be distinguished from cross-reactive antibodies. At least two distinct GAS exposures were detected in each of the ARF sera tested. Furthermore, no two sera had the same T-antigen reactivity profile suggesting that each patient was exposed to a unique series of GAS T-types prior to developing ARF. The methods have provided much-needed experimental evidence to substantiate the immune-priming hypothesis, and will facilitate further serological profiling studies that explore the multifaceted interactions between GAS and the host.

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.