Synthesising quantitative evidence in systematic reviews of complex health interventions

Public health and health service interventions are typically complex: they are multifaceted, with impacts at multiple levels and on multiple stakeholders. Systematic reviews evaluating the effects of complex health interventions can be challenging to conduct. This paper is part of a special series of papers considering these challenges particularly in the context of WHO guideline development. We outline established and innovative methods for synthesising quantitative evidence within a systematic review of a complex intervention, including considerations of the complexity of the system into which the intervention is introduced. We describe methods in three broad areas: non-quantitative approaches, including tabulation, narrative and graphical approaches; standard meta-analysis methods, including meta-regression to investigate study-level moderators of effect; and advanced synthesis methods, in which models allow exploration of intervention components, investigation of both moderators and mediators, examination of mechanisms, and exploration of complexities of the system. We offer guidance on the choice of approach that might be taken by people collating evidence in support of guideline development, and emphasise that the appropriate methods will depend on the purpose of the synthesis, the similarity of the studies included in the review, the level of detail available from the studies, the nature of the results reported in the studies, the expertise of the synthesis team and the resources available

Temperament Moderates Novel Word Learning at 15 Months

Researchers have been reporting temperament-language correlations in infants for 10 years. However, in order to identify directions of effects between temperament and language, methodologies besides correlations need to be developed. The “competition attention paradigm” is an effort to sidestep some of the direction-of-effect issues by asking infants to learn novel words in the context of environmental distractions designed to tap into children’s temperaments. The purpose of the present study was to explore whether environmental distracters would differentially impact 15-month-olds’ novel wordlearning as a function of children’s temperamental profiles. Twenty-eight 15-month-olds were asked to learn 4 novel words. Novel word learning consisted of initially familiarizing children with two novel objects, and then mapping a novel label to only one of the novel objects five times. Novel word comprehension was tested by asking children to select the newly-labeled object from the pair of novel objects across 4 test trials. A remotely-controlled mechanical spider competed for children’s attention during object familiarization on two of the words. Half the children were distracted on the first two words, half were distracted on the last two. Temperament was assessed via parental reporting using the Early Child Behavior Questionnaire. The environmental distractions did not impact children’s word-learning directly. However, order of distraction presentation did [F(1, 23) = 7.16, p = .014], such that children who were distracted on the first two words performed higher overall than children who were distracted on the last two. Results involving temperament were complex, yielding many significant interaction effects with factors impacting children’s word-learning. For example, children high in fear demonstrated better word-learning in the absence of the spider than in its presence, whereas the spider had no effect on low-fear children, but only when learning the first word in the pair [F(1, 23) = 5.20, p = .032]. Other temperament factors found to impact novel word-learning included attentional focus, cuddliness, impulsivity, frustration, and high intensity pleasure. The results of the present investigation contribute to a growing body of research linking temperament to word learning. The competition attention paradigm suggest ways through which word learning may be impacted by dimensions of temperament. Although not presentable here due to space limitations, the pattern of results also points to attentional focus as playing a central moderating role over other dimensions of temperament. Finally, the present results are the first to link temperament to language acquisition at 15 months

Using the HOME Inventory with Infants in Costa Rica

This study determined the psychometric properties of the HOME (Home Observation for Measurement of the Environment) Inventory in a Latin American sample. HOME data for 183 healthy Costa Rican infants were compared to the original HOME standardisation sample from Little Rock. The Costa Rican total HOME average of 29.8 ± 6.7 was similar to the scores of families in Little Rock (mean = 31.2 ± 7.3). Measures or internal consistency and factor structure were similar in US and Costa Rican samples. In contrast to these similarities, Costa Rican HOME scores showed no significant correlation with developmental test scores in infancy (Bayley MDI), and the correlation with Full Scale IQ (WPPSI) at five years was modest, albeit statistically significant (r = 0.28, P < 0.05). These relationships were similar to those of Mexican-American children in a recent collaborative study by Bradley et al., 1989 and not as strong as for US white and black populations. However, when the concept of outcome was broadened beyond IQ scores to include child health and development in general, the HOME seemed sensitive to important environmental differences in this Costa Rican group. Lower HOME scores related to a shorter duration of breastfeeding and differentiated children with iron deficiency anaemia in infancy, a condition associated with long-lasting developmental disadvantage. Thus, the HOME was helpful in identifying children at risk for delayed development in this Latin American sample.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67767/2/10.1177_016502549501800206.pd

Cancer Cluster Investigations: Review of the Past and Proposals for the Future

Residential clusters of non-communicable diseases are a source of enduring public concern, and at times, controversy. Many clusters reported to public health agencies by concerned citizens are accompanied by expectations that investigations will uncover a cause of disease. While goals, methods and conclusions of cluster studies are debated in the scientific literature and popular press, investigations of reported residential clusters rarely provide definitive answers about disease etiology. Further, it is inherently difficult to study a cluster for diseases with complex etiology and long latency (e.g., most cancers). Regardless, cluster investigations remain an important function of local, state and federal public health agencies. Challenges limiting the ability of cluster investigations to uncover causes for disease include the need to consider long latency, low statistical power of most analyses, uncertain definitions of cluster boundaries and population of interest, and in- and out-migration. A multi-disciplinary Workshop was held to discuss innovative and/or under-explored approaches to investigate cancer clusters. Several potentially fruitful paths forward are described, including modern methods of reconstructing residential history, improved approaches to analyzing spatial data, improved utilization of electronic data sources, advances using biomarkers of carcinogenesis, novel concepts for grouping cases, investigations of infectious etiology of cancer, and “omics” approaches