Designing Multidisciplinary Longitudinal Studies of Human Development

Prospective longitudinal study investigating predictors of childhood injuries from Growing Up in New Zealand cohort: study protocol

BACKGROUND

Injury is one of the leading causes of mortality and morbidity worldwide and yet preventable and predictable. In New Zealand (NZ), unintentional injury is the leading cause of emergency department visits, hospitalisations and death among children, making it a significant public health concern.

OBJECTIVE

To identify the factors that place young children in NZ at an increased risk of unintentional injury.

METHODS

This study will investigate injuries among children from the prospective Growing Up in NZ birth cohort of 6853 children and their families. The primary outcome of interest is injury events where medical treatment was sought. The data sources include parental reports of child injury and Accident Compensation Corporation-NZ's no-fault injury compensation system-injury claims. The linked datasets will be utilised to examine the distribution of life course exposures and outcome data using descriptive statistics. A temporal multilevel model will then be developed to examine relationships between neighbourhood, child and family characteristics and injury from birth to 5 years of age for all children for whom parental consent to link data were obtained.

DISCUSSION

The findings of this research will help to identify how the multiplicity of influences between children, family and their broader societal context acting across time affect their risk of experiencing a preschool injury. This information will provide an evidence base to inform context-relevant strategies to reduce and prevent childhood injuries.

Stop, think, reflect, realize-first-time mothers' views on taking part in longitudinal maternal health research

Background

Longitudinal cohort studies gather large amounts of data over time, often without direct benefit to participants. A positive experience may encourage retention in the study, and participants may benefit in unanticipated ways.

Objective

To explore first‐time mothers’ experiences of taking part in a longitudinal cohort study and completing self‐administered surveys during pregnancy and at 3, 6, 9 and 12 months’ postpartum.

Design

Content analysis of comments written by participants in the Maternal health And Maternal Morbidity in Ireland study's five self‐completion surveys, a multisite cohort study exploring women's health and health problems during and after pregnancy. This paper focuses on what women wrote about taking part in the research. Ethical approval was granted by the site hospitals and university.

Setting and participants

A total of 2174 women were recruited from two maternity hospitals in Ireland between 2012 and 2015.

Findings

A total of 1000 comments were made in the five surveys. Antenatally, barriers related to surveys being long and questions being intimate. Postpartum, barriers related to being busy with life as first‐time mothers. Benefits gained included gaining access to information, taking time to reflect, stopping to think and being prompted to seek help. Survey questions alone were described as valuable sources of information.

Discussion and conclusions

Findings suggest that survey research can “give back” to women by being a source of information and a trigger to seek professional help, even while asking sensitive questions. Understanding this can help researchers construct surveys to maximize benefits, real and potential, for participants.

'Telling our story... Creating our own history': caregivers' reasons for participating in an Australian longitudinal study of Indigenous children

BACKGROUND

Improving the wellbeing of Indigenous populations is an international priority. Robust research conducted with Aboriginal and Torres Strait Islander peoples is key to developing programs and policies to improve health and wellbeing. This paper aims to quantify the extent of participation in a national longitudinal study of Aboriginal and Torres Strait Islander (Indigenous Australian) children, and to understand the reasons why caregivers participate in the study.

METHODS

This mixed methods study uses data from Wave 6 of Footprints in Time, the Longitudinal Study of Indigenous Children. We conducted descriptive analysis of quantitative variables to characterise the sample and retention rates. We applied conventional content analysis to 160 caregivers' open-ended responses to the question, 'Why do you stay in the study?', identifying themes and overarching meta-themes.

RESULTS

The study has maintained a high retention rate, with 70.4% (n = 1239/1671) of the baseline sample participating in the study's 6th wave. We identified seven themes related to why participants stay in the study: telling our story, community benefit, satisfaction, tracking Study Child's progress, study processes, receiving study gifts, and valuing what the study stands for. These related to two meta-themes: reciprocity, and trust and connection. Caregivers reported that participation was associated with benefits for their family and community as well as for the study. They identified specific features of the Footprints in Time study design that built and maintained trust and connection between participants and the study.

CONCLUSIONS

Our findings support the assertion that Aboriginal and Torres Strait Islander people want to be involved in research when it is done 'the right way'. Footprints in Time has successfully recruited and retained the current-largest cohort of Aboriginal and Torres Strait Islander children in Australia through the use of participatory research methodologies, suggesting effective study implementation and processes. Participants indicated ongoing commitment to the study resulting from perceptions of reciprocity and development of trust in the study. Footprints in Time can serve as a successful model of Aboriginal and Torres Strait Islander health research, to promote good research practice and provides lessons for research with other Indigenous populations.

Comparison of Recruitment Strategy Outcomes in the National Children's Study

BACKGROUND AND OBJECTIVES

In 2000, the US Congress authorized the National Institutes of Health to conduct a prospective national longitudinal study of environmental influences on children's health and development from birth through 21 years. Several recruitment methodologies were piloted to determine the optimal strategy for a main National Children's Study.

METHODS

After an initial pilot recruitment that used a household enumeration strategy performed poorly, the National Children's Study Vanguard Study developed and evaluated the feasibility, acceptability, and cost of 4 alternate strategies to recruit a large prospective national probability sample of pregnant women and their newborn children. We compare household-based recruitment, provider-based recruitment, direct outreach, and provider-based sampling (PBS) strategies with respect to overall recruitment success, efficiency, cost, and fulfillment of scientific requirements.

RESULTS

Although all 5 strategies achieved similar enrollment rates (63%-81%) among eligible women, PBS achieved the highest recruitment success as measured by the ratio of observed-to-expected newborn enrollees per year of 0.99, exceeding those of the other strategies (range: 0.35-0.48). Because PBS could reach the enrollment target through sampling of high volume obstetric provider offices and birth hospitals, it achieved the lowest ratio of women screened to women enrolled and was also the least costly strategy. With the exception of direct outreach, all strategies enrolled a cohort of women whose demographics were similar to county natality data.

CONCLUSIONS

PBS demonstrated the optimal combination of recruitment success, efficiency, cost, and population representativeness and serves as a model for the assembly of future prospective probability-based birth cohorts.

Factors relating to participation in follow-up to the 45 and up study in Aboriginal and non-Aboriginal individuals

Background

This study aimed to characterise the factors relating to participation in a postal follow-up study in Aboriginal and non-Aboriginal individuals, given the need to quantify potential biases from loss to follow-up and the lack of evidence regarding postal surveys among Aboriginal people.

Methods

The first 100,000 participants from the Sax Institute’s 45 and Up Study, a large scale cohort study, were posted a follow-up questionnaire gathering general demographic, health and risk factor data, emphasising Social, Economic and Environmental Factors (“The SEEF Study”). For each variable of interest, percentages of those invited who went on to participate in follow-up were tabulated separately for Aboriginal and non-Aboriginal participants and age- and sex-adjusted participation rate ratios (aPRR) were calculated.

Results

Of the 692 Aboriginal and 97,178 non-Aboriginal invitees to the study, 314 Aboriginal (45 %) and 59,175 non-Aboriginal (61 %) individuals responded. While Aboriginal people were less likely to respond than non-Aboriginal people (aPRR 0.72, 95 % CI 0.66–0.78), factors related to response were similar. Follow-up study participants were more likely than non-participants to have university versus no educational qualifications (1.6, 1.3–2.0 [Aboriginal]; 1.5, 1.5–1.5 [non-Aboriginal]) and an annual income of ≥70,000 versus < $20,000 (1.6, 1.3–2.0; 1.2, 1.2–1.3 [χ² = 7.7; p = 0.001]). Current smokers (0.55, 0.42–0.72; 0.76, 0.74–0.77 [χ² = 7.14; p = 0.03]), those reporting poor self-rated health (0.68, 0.47–0.99; 0.65, 0.61–0.69), poor quality of life (0.63, 0.41–0.97; 0.61, 0.57–0.66) and very high psychological distress (0.71, 0.68–0.75 [non-Aboriginal]) were less likely than other cohort members to respond.

Conclusions

Relatively large numbers of Aboriginal and non-Aboriginal individuals participated in the first 45 and Up Study follow-up suggesting that postal surveys can be used to follow Aboriginal participants in cohort studies. Despite somewhat greater loss to follow-up in Aboriginal people (after considering socio-demographic and health characteristics), factors related to follow-up participation were similar in both groups: greater loss was observed in those experiencing disadvantage, ill-health and health risk, with implications for interpretation of future findings. Aboriginal low income earners and current regular smokers had a particularly elevated likelihood of non-participation compared to non-Aboriginal people. These findings highlight the importance of identifying and addressing barriers to participation among hard-to-reach population groups.

Electronic supplementary material

The online version of this article (doi:10.1186/s12874-016-0155-x) contains supplementary material, which is available to authorized users.

Longitudinal Intergenerational Birth Cohort Designs: A Systematic Review of Australian and New Zealand Studies

Background

The longitudinal birth cohort design has yielded a substantial contribution to knowledge of child health and development. The last full review in New Zealand and Australia in 2004 identified 13 studies. Since then, birth cohort designs continue to be an important tool in understanding how intrauterine, infant and childhood development affect long-term health and well-being. This updated review in a defined geographical area was conducted to better understand the factors associated with successful quality and productivity, and greater scientific and policy contribution and scope.

Methods

We adopted the preferred reporting items for systematic reviews and meta-analyses (PRISMA) approach, searching PubMed, Scopus, Cinahl, Medline, Science Direct and ProQuest between 1963 and 2013. Experts were consulted regarding further studies. Five inclusion criteria were used: (1) have longitudinally tracked a birth cohort, (2) have collected data on the child and at least one parent or caregiver (3) be based in Australia or New Zealand, (4) be empirical in design, and (5) have been published in English.

Results

10665 records were initially retrieved from which 23 birth cohort studies met the selection criteria. Together these studies recruited 91,196 participants, with 38,600 mothers, 14,206 fathers and 38,390 live births. Seventeen studies were located in Australia and six in New Zealand. Research questions initially focused on the perinatal period, but as studies matured, longer-term effects and outcomes were examined.

Conclusions

This review demonstrates the significant yield from this effort both in terms of scientific discovery and social policy impact. Further opportunities have been recognised with cross-study collaboration and pooling of data between established and newer studies and international studies to investigate global health determinants.

A systematic review of the effect of retention methods in population-based cohort studies

Background

Longitudinal studies are of aetiological and public health relevance but can be undermined by attrition. The aim of this paper was to identify effective retention strategies to increase participation in population-based cohort studies.

Methods

Systematic review of the literature to identify prospective population-based cohort studies with health outcomes in which retention strategies had been evaluated.

Results

Twenty-eight studies published up to January 2011 were included. Eleven of which were randomized controlled trials of retention strategies (RCT). Fifty-seven percent of the studies were postal, 21% in-person, 14% telephone and 7% had mixed data collection methods. A total of 45 different retention strategies were used, categorised as 1) incentives, 2) reminder methods, repeat visits or repeat questionnaires, alternative modes of data collection or 3) other methods. Incentives were associated with an increase in retention rates, which improved with greater incentive value. Whether cash was the most effective incentive was not clear from studies that compared cash and gifts of similar value. The average increase in retention rate was 12% for reminder letters, 5% for reminder calls and 12% for repeat questionnaires. Ten studies used alternative data collection methods, mainly as a last resort. All postal studies offered telephone interviews to non-responders, which increased retention rates by 3%. Studies that used face-to-face interviews increased their retention rates by 24% by offering alternative locations and modes of data collection.

Conclusions

Incentives boosted retention rates in prospective cohort studies. Other methods appeared to have a beneficial effect but there was a general lack of a systematic approach to their evaluation.

What have birth cohort studies asked about genetic, pre- and perinatal exposures and child and adolescent onset mental health outcomes? A systematic review

Increased understanding of early neurobehavioural development is needed to prevent, identify, and treat childhood psychopathology most effectively at the earliest possible stage. Prospective birth cohorts can elucidate the association of genes, environment, and their interactions with neurobehavioural development. We conducted a systematic review of the birth cohort literature. On the basis of internet searches and 6,248 peer-reviewed references, 105 longitudinal epidemiological studies were identified. Twenty studies met inclusion criteria (prospectively recruited, population-based cohort studies, including at least one assessment before the end of the perinatal period and at least one assessment of behaviour, temperament/personality, neuropsychiatric or psychiatric status before 19 years of age), and their methodologies were reviewed in full. Whilst the birth cohort studies did examine some aspects of behaviour and neurodevelopment, observations in the early months and years were rare. Furthermore, aspects of sampling method, sample size, data collection, design, and breadth and depth of measurement in some studies made research questions about neurodevelopment difficult to answer. Existing birth cohort studies have yielded limited information on how pre- and perinatal factors and early neurodevelopment relate to child psychopathology. Further epidemiological research is required with a specific focus on early neurodevelopment. Studies are needed which include the measures of early childhood psychopathology and involve long-term follow-up.

Sex differences in the effects of neighborhood socioeconomic disadvantage and social organization on rural adolescents' aggression trajectories

We determined whether effects of neighborhood socioeconomic disadvantage on trajectories of aggression were moderated or mediated by neighborhood social organization and examined sex differences in neighborhood effects for rural adolescents. We used five waves of survey data collected over 2.5 years linked with neighborhood data from interviews with parents and the US Census. The sample (N = 5,118) was 50.1% female, 52.0% white and 38.3% African-American; average age at baseline was 13.1 years. Multilevel growth curve models for both girls and boys showed no significant interactions between neighborhood socioeconomic disadvantage and indicators of social organization. Neither sample showed evidence of mediated effects. In main effects models, neighborhood disadvantage was associated with the average aggression trajectory for girls. For boys, the effects of neighborhood socioeconomic disadvantage and social disorganization appeared to be confounded with each other. Neighborhood disadvantage is detrimental for rural girls regardless of the level of social organization.