![]()
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Pacific Islands Families: First Two Years of Life
Study—design and methodology
Janis Paterson, Colin Tukuitonga, Max Abbott, Michael
Feehan, Phil Silva, Teuila Percival, Sarnia Carter, Esther Cowley-Malcolm, Jim
Borrows, Maynard Williams, Philip Schluter
Following the Second World
War, links between Pacific Island groups and the countries around the Pacific
Rim intensified and mobility within the region increased substantially.1
Migration, sometimes supported by intergovernmental agreements, was fuelled by
the search for employment and a higher standard of living2, resulting in 400,000
people of Pacific Islands ethnicity living in the Rim countries of the Pacific
by the mid-1990s.3
Migration to New Zealand has
been historically popular since the 1960s, due mostly to its proximity to the
Pacific Islands but also due to labour demands resulting from economic growth in
the New Zealand economy.4
As one of the fastest growing
population subgroups in New Zealand, Pacific peoples (those residents with a
Pacific Islands heritage) form an integral part of New Zealand society.5 The
Pacific population in New Zealand is now estimated to exceed 284,000,6
comprising 6.8% of the New Zealand population, and Auckland is the preferred
region of domicile.7 Samoans constitute the largest group (50%), followed by
Cook Island Maori (23%), Tongan (18%), Niuean (9%), Fijian (3%), Tokelauan (3%),
and Tuvalu Islanders (1%).7 This ethnic diversity is manifest in differing
cultures, languages, strength of acculturation, and corresponding access to (and
utilisation of) health and social services.
Despite better employment
opportunities in New Zealand, Pacific peoples remain relatively
socioeconomically disadvantaged. Their labour force participation and annual
median income are lower than in the total population. Pacific people are more
likely to be living in poor circumstances with restricted access to higher
education, home ownership, and access to functional amenities such as
automobiles and telephones. They are also over-represented in multiple adverse
health and social statistics.7,8
Furthermore, the health of
Pacific infants continues to be an issue of concern with the Pacific infant
death rate being higher than the national infant death rate since 1997.7 Pacific
infants have high rates of hospitalisation (particularly for respiratory
illnesses)8,9 and present at hospital with higher severity of illness than New
Zealand children of other ethnicities.10
In an effort to explore and
understand both positive and negative facets of Pacific families’ life in
New Zealand, the Pacific Islands Families: First Two Years of Life (PIF) Study
was instigated. This prospective longitudinal study follows a cohort of Pacific
children and their families in order to track the children’s development
and wellbeing.
Several theoretical and
research perspectives (focussing on individual, family, community, and societal
influences on development, health, and wellbeing) underpin this study. These
include infant development;11,12 temperament;13–15, attachment;16,17
mutual regulation of infant and caregiver behaviours;18 parenting;19–21
home environment;22,23 social support;24 acculturative stress;25 and the
ecological approach emphasising the role of macro-level economic, social, and
cultural factors.26
In addition to broader
contextual factors, parenting and lifestyle behaviours develop according to
different cognitive, linguistic, motivational, and social competencies that are
relevant to each culture.27,28 The ‘transactional model’ of human
development,29,30 acknowledging the interaction between various influences, will
form the basis for the testing of more specific models to account for how the
child develops within the context of a Pacific family.
The PIF study’s initial
focus is on the key developmental stage of early infancy and the influence of
the sociocultural context and family environment on Pacific children at ages 6
weeks, 12 months, and 24 months. The PIF study design is multidisciplined,
broad-based and inclusive—capturing information from mothers, fathers, and
infants.
General aims of the PIF study
are to:
The specific aims
of the PIF study (separated by the major health, psychosocial, and behavioural
domains) appear in Table 1.
The study will provide ethnic-specific information to a
variety of end-users on which to base interventions and inform policy
development to help address many negative health and social issues that face
Pacific children and families.
MethodsDesign—Mothers
of a cohort of live Pacific Islands infants born at Middlemore Hospital, South
Auckland, between 15 March and 17 December 2000 were recruited.
An infant was deemed eligible if at least one parent
identified themselves as being of Pacific Islands ethnicity and was a permanent
resident of New Zealand. Presentation of study information to mothers and
subsequent recruitment was completed within the hospital setting. Maternal home
interviews were undertaken at approximately 6-weeks, 12-months, and 24-months
postpartum; and paternal home interviews were conducted at approximately
12-months and 24-months postpartum.
At 12-months and 24-months, a developmental assessment
of the child’s adaptive functioning was also undertaken in the family
home. Prior to the commencement of the main study, extensive community
consultation, staff training, and piloting was undertaken. Formal community
liaison commenced in 1996L ethical clearance was received in May 1999; formal
consent to recruit mothers at Middlemore was obtained on 10 June 1999; and all
60 mothers giving birth to Pacific infants between 12 July and 24 July 1999 were
approached for recruitment into the pilot study.
Participant tracking databases and contact strategies
for both mothers and fathers were developed; interview questionnaires were
tested and timed; and data entry and management systems established during this
piloting phase.
Recruitment—Promotional
material was made available through various sources prior to hospital
admission—including media, community meetings, antenatal classes and Lead
Maternity Carers (LMCS). Eroni Clarke, a former New Zealand All Black rugby
player born in Samoa, featured on posters and brochures to raise awareness of
the study.
Participant eligibility identification was made through
the Birthing Unit in conjunction with the Pacific Islands Cultural Resource Unit
that provided a daily printout of Pacific admissions. These were checked for
Pacific births and crosschecked with the daily records held in the Birthing
Unit.
Under the supervision of Middlemore clinical staff, the
Auckland University of Technology (AUT) Pasifika Development Manager (PDM) or
the Pacific Liaison Officer (PLO) made the initial approach to identified
potential participants; provided brief information about the study; and obtained
permission for later contact.
Informed consent was not sought at this point. For
potential participants who were not seen at Middlemore Hospital, either because
they were discharged home early or transferred to one of the two satellite
hospitals, the initial visit was made by the PLO at a location convenient for
the mother.
Approximately 6-weeks postpartum, potential
participants were allocated to a team of female Pacific interviewers fluent in
both English and a Pacific language. In most cases, the interviewers were
ethnically matched to the potential participant. The interviewers visited the
potential participant in their own homes, fully described the study with the
parent(s), and obtained the mother’s informed consent. Once consent was
obtained, the interview was carried out in the mother’s preferred
language.
When the children reached their first and second
birthdays, all maternal participants were re-contacted and revisited by a female
Pacific interviewer. Again, consent was obtained before the interview was
conducted in the mother’s preferred language. At the time of the
interview, mothers were asked to give permission for a male Pacific interviewer
to contact and interview the father of the child. If permission and paternal
contact details were obtained, then a Pacific male interviewer contacted the
father to discuss participation in the study. Once informed consent was obtained
from the father, the interview was carried out in the father’s preferred
language.
Data
collection—Survey instruments are considered relevant and
appropriate by both researchers and the Pacific community. Pacific researchers
have considerable input into the general measurement framework and specific
measures employed to ensure their content acceptability and validity. Where
possible, standardised internationally developed measures and scales are used or
adapted for the PIF study.
The use of such scales ensures constructs (universal
across cultures) are measured and information considered important to child
health and development is elicited. Measures employed during the pilot phase
that had unsatisfactory reliability and/or validity were removed. Some measures
underwent focus group examination to check wording of items and testing
procedures.31,32 However, the psychometric properties of most standardised
measures used in the pilot were acceptable, and few modifications were required.
Table 2 includes the specific dimensions and instruments employed in the main
PIF study.
The interview protocol used at the 6-weeks phase was
translated into Samoan, Tongan, and Cook Island Maori and checked by fluent
speakers of these Pacific languages for clarity of exposition and concept
integrity. Only 174 (13%) mothers utilised a non-English version, the majority
of these being Tongan. As such, the interview protocols used at the 12-month and
24-month phases were made available in English and Tongan only.
With mother’s consent, supplementary information
was obtained from both Middlemore Hospital and Plunket. Maternal obstetric
history, delivery details, and infant measures of birth weight for gestational
age, head circumference, Apgar scores, and neonatal care were obtained from
Middlemore’s Hospital Discharge Summary records. Information about
infant’s physical status was obtained from the comprehensive physical
assessment carried out by Plunket at 6-weeks and 6-months postpartum.
Data
accuracy—Various systems were implemented to ensure data accuracy
and consistency. These included: manual coding of each interview protocol to
check consistency within the individual interview; accompanying interviewers to
check on rapport, informed consent and on the undertaking of standard
procedures; and post-interview random phone checks with participants to clarify
and confirm specific details of the interviews.
Data entry and
security—Two researchers developed codes based on the first 50
cases for the open-ended questions and interviewer observations. All data are
double entered into an electronic database (SPSS Data Entry Builder 2.0) that
employs comprehensive data validation and checking rules. This database includes
no personal identification and is held in secure password protected storage
under the responsibility of the PIF study’s Co-Directors in accordance
with the requirements of the New Zealand Privacy Act (1993) and the Health
Information Privacy Code (1994).
Participant labelling in this database is made by
reference number only. Identification information is stored on a separate
computer in a password-protected file. All interviews are confidential, and only
PIF study staff authorised by the Co-Directors have access to computerised data.
All information is treated as sensitive data. Participants own their data and
reserve the right to withdraw it at any time.
Sample
size—Balancing the competing demands for increased statistical
power in longitudinal studies33 against conducting a feasible, efficient, and
cost-effective study, a final cohort of approximately 1000 mothers of Pacific
infants at 24-months was targeted. To compensate for likely attrition (assumed
to be 10% per measurement wave), it was determined that approximately 1400
eligible mothers needed to be recruited. This sized cohort would generally have
adequate power for inter-ethnic comparisons of major groups such as Samoan,
Tongan, and Cook Islands Maori. However, it is recognised that power will not
always be adequate for analyses involving smaller ethnic groups; for the
detection of small differences between groups; or for more complex analyses
involving a greater number of categories (e.g. different feeding methods in
Islands-born versus NZ-born Tongans).
Statistical
analyses—In terms of the more general analytic approach,
cross-sectional analyses at each assessment time will be undertaken, allowing
the prevalence of key outcomes to be estimated, as well as the association
between risk factors and key outcome variables. Longitudinal analysis techniques
will be used in the modelling of developmental pathways including structural
equation modelling, mixed linear models, and generalised estimating equations.
The gathering of data from mothers, fathers, and secondary sources allows the
concordance between reports of child outcomes and parental functioning to be
assessed.
Fisher’s exact test was employed to determine
whether differential attrition existed over time for a selection of basic
sociodemographic variables. Differential attrition would have occurred if both
12-month and 24-month distributions of participation and
non-participation were
significantly different to the 6-week distributions, using a significance level
α=0.05 to define statistical significance.
Ethics—Careful
consideration is continually given to the ethical aspects of this longitudinal
study with Pacific peoples. Ethical approval for the pilot and main PIF study
was obtained from the Auckland Branch of the National Ethics Committee, the
Royal New Zealand Plunket Society, and the South Auckland Health Clinical
Board.
ResultsOf the mothers with Pacific infants who had been born at
Middlemore Hospital between 15 March and 17 December 2000, 1590 gave consent to
the 6-week postpartum home visit. The recruitment and participation rate at the
6-weeks, 12-months, and 24-months interview schedule is depicted in Figure
1.
From the 1376 primary
respondents of the cohort at 6-weeks, there were 1368 biological mothers, 1
foster mother, 6 adoptive mothers, and 1 grandmother. For ease of exposition, we
shall refer to this group collectively as ‘mothers’ hereafter.
Twenty-three of the 1376 mothers gave birth to twins, but as one twin member was
stillborn the overall number of children forming this cohort totalled 1398. Of
these, 374 (27%) infants were first-born and 1339 (96%) infants were discharged
with their mothers from hospital. Middlemore hospital records revealed that the
mean birth weight was 3584 grams (SD: 613 grams) with a range of 650 to 5390
grams.
The mean age of all mothers
was 27.9 years (SD: 6.2 years), the range was 14 to 57 years, and 8% of mothers
were younger than 20 years (see Table 3). Most (1107 [80%]) mothers were living
together in married or de facto partnerships. 454 (33%) mothers were New
Zealand-born. In terms of schooling, 535 (39%) mothers had no formal educational
qualifications, 464 (34%) had secondary school qualifications only, and 377
(27%) had post-school qualifications.
Ethnicity of mothers was self-identified and also coded
according to the sub-groupings of the 1996 Census. Of the cohort mothers, 650
(47%) self identified their major ethnic group as Samoan; 289 (21%) as Tongan;
232 (17%) as Cook Islands Maori; 59 (4%) as Niuean; 47 (3%) as Other Pacific
(this includes mothers identifying equally with two or more Pacific groups,
equally with Pacific and Non-Pacific groups, or with Pacific groups other than
Samoan, Tongan, Cook Island, or Niuean); and 99 (7%) as Non-Pacific. These
frequencies are broadly similar to those seen in the New Zealand Pacific Island
population.7
No important differential
attrition was observed for any of the sociodemographic variables investigated in
Table 3. While the distribution of participants was statistically different to
non-participants at 12-months for ethnicity (p=0.001) and years lived in New
Zealand (p=0.007), no such difference existed at 24-months (ethnicity, p=0.20;
years lived in New Zealand, p=0.15).
999 of the mothers interviewed at 12-months had partners who
met eligibility criteria to act as collateral respondents, of whom 825 (83%)
were interviewed. Most (820 [99%]) fathers interviewed at 1 year were the
biological fathers of the children, with five adoptive or stepfathers. Again,
for ease of exposition, we shall refer to this group collectively as
‘fathers’ hereafter. Most (786 [95%]) fathers were living with the
biological mother of the child in a married (77%) or de facto (18%)
relationship. The mean age was 32.1 years (SD: 7.3 years), the range was 17 to
65 years, and 1% of the fathers were younger than 20 years.
Approximately one-quarter (203 [25%]) of the fathers were
born in New Zealand. 440 fathers (53%) self-identified their major ethnic group
as Samoan; 199 (24%) as Tongan; 73 (9%) as Cook Islands Maori; 26 (3%) as
Niuean; 28 (3%) as Other Pacific (this includes fathers identifying equally with
two or more Pacific groups, equally with Pacific and Non-Pacific groups, or with
Pacific groups other than Samoan, Tongan, Cook Island or Niuean); and 59 (7%) as
Non-Pacific.
In terms of education, 481 (58%) fathers had no formal
educational qualifications, 220 (27%) had a secondary school qualification only,
and 122 (15%) had a post-school qualification.
Of the 757 secondary respondents interviewed at 24-months,
almost all (754 [99%]) were the biological fathers of the children in the cohort
with three adoptive or stepfathers. There were no significant differences in
age, martial status, smoking status, highest educational qualification, English
fluency, and household income demographics of this group compared to that
interviewed at 12-months. However, there were fewer Tongan fathers interviewed
at 24-months (20% vs 24%, p<0.001), and more who had lived in New Zealand for
over a decade (42% vs 40%, p=0.002).
Birth mothers served as respondents for all child
assessments at 12-months and for 97% of 1,064 child assessments at 24-months
postpartum. Mean height and weight of the children at 24-months was 89.0 cm (SD:
4.4 cm) and 14.4 kg (SD: 2.2 kg) respectively.
DiscussionThe PIF study is a large, scientifically and culturally
robust longitudinal study that has achieved respectable participation rates over
the first 24-months of its life. Both maternal and paternal figures have the
opportunity to participate, something that has been rarely undertaken in
previous longitudinal studies of this nature. Both parental figures have been
highly responsive and receptive to our invitation to participate in each of the
measurement waves despite the many demands upon their time.
We believe this stems from several important design
attributes embedded within the PIF study, including: the integration of Pacific
people in all aspects of the study; the single-based hospital design; and having
home-visits conducted by ethnic and gender-matched interviewers.
The integral involvement with Pacific people in the
consultation, design, development of the interview protocols and instruments,
recruitment, elicitation, and interpretation of information and governance of
the study is critical. Such input gives credibility, cultural appropriateness,
and Pacific community involvement and ownership of the study. These features
coupled with the perceived importance and relevance of the study’s
contents by the participants themselves should ensure that response rates remain
respectable throughout.
The PIF study directors are guided by the Pacific
Peoples’ Advisory Board who monitored the general direction of the study.
The Board’s primary responsibility is to protect and enhance the study to
maximise benefits for Pacific communities. In addition, through the sharing
between Pacific and non-Pacific researchers, the PIF study serves as a useful
platform for the advancement and training of Pacific researchers and field
staff.
A single hospital-based recruitment catchment enabled the
target population to be easily identified and accessed; streamlines and enhances
the cost-effectiveness of procedures for the approach and recruitment; and
increases the ‘health’ credibility of the study for the
participants. Also, this institutional sampling frame lends itself to a
‘study champion’; a person or persons with considerable passion and
vigour, who understands the local system and ensures smooth running of study.
Both the PDM and PLO performed well in this capacity for the PIF study.
Instrumental in the PIF study’s recruitment and
retention success to date are the research base for fieldwork staff and the home
visits by ethnic and gender matched bilingual or multilingual Pacific
interviewers. The research base was a readily identifiable ‘home’
for the field workers—where they engaged, learnt, and developed with
fellow colleagues and the study investigators. In terms of home visitations,
participants find them convenient and comfortable, particularly for those
without private transportation. Moreover, they find the experience less
disruptive for the family especially if they have other children who need
attention.
The ethnic and gender-matched bilingual or multilingual
Pacific interviewers facilitates the development of a rapport between themselves
and the participants, and language barriers or difficulties are circumvented.
The availability of survey instruments in English, Samoan, Tongan, and Cook
Island Maori, in the first instance, probably contributed to the strong
participant response.
Other design efficiencies included the utilisation of data
from alternative available sources, such as Middlemore Hospital Discharge
Summary records and Plunket’s records including the comprehensive physical
assessment. The capture and use of these data decreases participant burden and
thereby is likely to increase participation rates. Additionally, use of the data
‘value-adds’ to the records collected by each of these organisations
themselves.
While also a strength, a weakness of the PIF study is that
it only included infants born at Middlemore Hospital in the sampling frame. It
could be opined that this may impinge on the representiveness and
generalisability of the study’s findings. However, more Pacific infants
are born at Middlemore than any other New Zealand hospital and we demonstrate
that the proportions of Pacific ethnic subgroups enrolled were broadly similar
to national proportions which suggest that any inherent biases due to this
recruitment strategy are likely to be small.
Although not a weakness in the PIF study itself, the lack of
equivalent contemporaneous data for other non-Pacific ethnic groups means that
interethnic group comparisons cannot be readily made. Recognising this
deficiency, the Ministry of Social Development and Heath Research Council of New
Zealand recently called for proposals for a longitudinal study of New Zealand
Children and Families.34
Because of the success of the PIF study, the
Pacific Islands Families Study: Transition to
School (PIF: TTS) was conceived
and launched in 2004. This successor study follows the PIF cohort of Pacific
children and their families, and aims to assess the children’s development
and wellbeing at ages 4 and 6 years. In particular, this study will focus on the
cohort and their families as they negotiate critical developmental transitions,
notably the transition to school.
The PIF study has been designed to advance scientific
knowledge in a number of disciplines and provide public benefits through the
provision of good quality information. It is envisaged that findings from this
study will inform policy development and assist programme implementation for a
variety of stakeholders working towards maximising the potential of Pacific
families and communities within broader New Zealand society. With the large,
scientifically and culturally robust study that has achieved respectable
participation rates, we believe these aims will be met.
Author information:
Janis Paterson, Associate Professor and Co-Director, Pacific Islands Families:
First Two Years of Life Study1; Colin Tukuitonga, former Co-Director, Pacific
Islands Families: First Two Years of Life Study1 and Pacific Health Research
Centre, Department of Maori & Pacific Island Health2; Max Abbott, Pro
Vice-Chancellor and Dean1; Michael Feehan, Adjunct Associate Professor1 and
Co-President3; Phil Silva, Adjunct Professor1 and Founding Director, Dunedin
Multidisciplinary Health & Development Research Unit4; Teuila Percival,
Paediatrician5; Sarnia Carter, Research Fellow, Pacific Islands Families: First
Two Years of Life Study1; Esther Cowley-Malcolm, Manager, Pacific Research
Workforce Development, Pacific Islands Families: First Two Years of Life Study1;
Jim Borrows, Research Manager1; Maynard Williams, Senior Research Fellow and
Statistician1; Philip Schluter, Professor of Biostatistics1.
Acknowledgements:
The Pacific Islands Families: First Two Years of Life (PIF) Study is
supported by grants awarded from the Foundation for Science, Research and
Technology; the Health Research Council of New Zealand; and the Maurice and
Phyllis Paykel Trust. The authors also gratefully acknowledge the families who
participated in the study; the Pacific Peoples Advisory Board; and the other
members of the PIF research team.
Correspondence:
Professor Philip Schluter, Faculty of Health & Environmental Sciences,
Auckland University of Technology, Private Bag 92006, Auckland 1020. Fax: (09)
921 9877; email: philip.schluter@aut.ac.nz
References:
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Current
issue | Search journal |
Archived issues | Classifieds
| Hotline (free ads) Subscribe | Contribute | Advertise | Contact Us | Copyright | Other Journals |