Risk management for drinking water safety in low and middle income countries - cultural influences on water safety plan (WSP) implementation in urban water utilities.

We investigated cultural influences on the implementation of water safety plans (WSPs) using case studies from WSP pilots in India, Uganda and Jamaica. A comprehensive thematic analysis of semi-structured interviews (n=150 utility customers, n=32 WSP 'implementers' and n=9 WSP 'promoters'), field observations and related documents revealed 12 cultural themes, offered as 'enabling', 'limiting', or 'neutral', that influence WSP implementation in urban water utilities to varying extents. Aspects such as a 'deliver first, safety later' mind set; supply system knowledge management and storage practices; and non-compliance are deemed influential. Emergent themes of cultural influence (ET1 to ET12) are discussed by reference to the risk management, development studies and institutional culture literatures; by reference to their positive, negative or neutral influence on WSP implementation. The results have implications for the utility endorsement of WSPs, for the impact of organisational cultures on WSP implementation; for the scale-up of pilot studies; and they support repeated calls from practitioner communities for cultural attentiveness during WSP design. Findings on organisational cultures mirror those from utilities in higher income nations implementing WSPs - leadership, advocacy among promoters and customers (not just implementers) and purposeful knowledge management are critical to WSP success.

Classification and Clustering Methods for Multiple Environmental Factors in Gene-Environment Interaction: Application to the Multi-Ethnic Study of Atherosclerosis.

There has been an increased interest in identifying gene-environment interaction (G × E) in the context of multiple environmental exposures. Most G × E studies analyze one exposure at a time, but we are exposed to multiple exposures in reality. Efficient analysis strategies for complex G × E with multiple environmental factors in a single model are still lacking. Using the data from the Multiethnic Study of Atherosclerosis, we illustrate a two-step approach for modeling G × E with multiple environmental factors. First, we utilize common clustering and classification strategies (e.g., k-means, latent class analysis, classification and regression trees, Bayesian clustering using Dirichlet Process) to define subgroups corresponding to distinct environmental exposure profiles. Second, we illustrate the use of an additive main effects and multiplicative interaction model, instead of the conventional saturated interaction model using product terms of factors, to study G × E with the data-driven exposure subgroups defined in the first step. We demonstrate useful analytical approaches to translate multiple environmental exposures into one summary class. These tools not only allow researchers to consider several environmental exposures in G × E analysis but also provide some insight into how genes modify the effect of a comprehensive exposure profile instead of examining effect modification for each exposure in isolation.

Modelling the global competing risks of a potential interaction between injectable hormonal contraception and HIV risk.

BACKGROUND: Some, but not all, observational studies have suggested an increase in the risk of HIV acquisition for women using injectable hormonal contraception (IHC). METHODS: We used country-level data to explore the effects of reducing IHC use on the number of HIV infections, the number of live births and the resulting net consequences on AIDS deaths and maternal mortality for each country. RESULTS: High IHC use coincides with high HIV incidence primarily in southern and eastern Africa. If IHC increases the risk of HIV acquisition, this could generate 27 000-130 000 infections per year globally, 87-88% of which occur in this region. Reducing IHC use could result in fewer HIV infections but also a substantial increase in live births and maternal mortality in countries with high IHC use, high birth rates and high maternal mortality: mainly southern and eastern Africa, South-East Asia, and Central and South America. For most countries, the net impact of reducing IHC use on maternal and AIDS-related deaths is dependent on the magnitude of the assumed IHC-HIV interaction. CONCLUSIONS: If IHC use increases HIV acquisition risk, reducing IHC could reduce new HIV infections; however, this must be balanced against other important consequences, including unintended pregnancy, which impacts maternal and infant mortality. Unless the true effect size approaches a relative risk of 2.19, it is unlikely that reductions in IHC could result in public health benefit, with the possible exception of those countries in southern Africa with the largest HIV epidemics.