A Simultaneous Equation Approach to Estimating HIV Prevalence with Non-Ignorable Missing Responses

Estimates of HIV prevalence are important for policy in order to establish the health status of a country's population and to evaluate the effectiveness of population-based interventions and campaigns. However, participation rates in testing for surveillance conducted as part of household surveys, on which many of these estimates are based, can be low. HIV positive individuals may be less likely to participate because they fear disclosure, in which case estimates obtained using conventional approaches to deal with missing data, such as imputation-based methods, will be biased. We develop a Heckman-type simultaneous equation approach which accounts for non-ignorable selection, but unlike previous implementations, allows for spatial dependence and does not impose a homogeneous selection process on all respondents. In addition, our framework addresses the issue of separation, where for instance some factors are severely unbalanced and highly predictive of the response, which would ordinarily prevent model convergence. Estimation is carried out within a penalized likelihood framework where smoothing is achieved using a parametrization of the smoothing criterion which makes estimation more stable and efficient. We provide the software for straightforward implementation of the proposed approach, and apply our methodology to estimating national and sub-national HIV prevalence in Swaziland, Zimbabwe and Zambia.

Influence of Heterogamy by Religion on Risk of Marital Dissolution: A Cohort Study of 20,000 Couples

Heterogamous marriages, in which partners have dissimilar attributes (e.g. by socio-economic status or ethnicity), are often at elevated risk of dissolution. We investigated the influences of heterogamy by religion and area of residence on risk of marital dissolution in Northern Ireland, a country with a history of conflict and residential segregation along Catholic–Protestant lines. We expected Catholic–Protestant marriages to have elevated risks of dissolution, especially in areas with high concentrations of a single religious group where opposition to intermarriage was expected to be high. We estimated risks of marital dissolution from 2001 to 2011 for 19,791 couples drawn from the Northern Ireland Longitudinal Study (a record linkage study), adjusting for a range of compositional and contextual factors using multilevel logistic regression. Dissolution risk decreased with increasing age and higher socio-economic status. Catholic–Protestant marriages were rare (5.9 % of the sample) and were at increased risk of dissolution relative to homogamous marriages. We found no association between local population composition and dissolution risk for Catholic–Protestant couples, indicating that partner and household characteristics may have a greater influence on dissolution risk than the wider community.

The impact of childhood residential mobility on mental health outcomes in adolescence and early adulthood: a record linkage study.

Background Understanding the causes of poor mental health in early childhood and adolescence is important as this can be a significant determinant of mental well-being in later years. One potential and relatively unexplored factor is residential mobility in formative years. Previous studies have been relatively small and potentially limited due to methodological issues. The main aim of this study was to investigate the relationship between early residential instability and poor mental health among adolescents and young adults in Northern Ireland.

Methods A Census-based record linkage study of 28% of children aged 0–8 years in 2001 in Northern Ireland (n=49 762) was conducted, with six monthly address change assessments from health registration data and self-reported mental health status from the 2011 Census. Logistic regression models were built adjusting for socioeconomic status (SES), household composition and marital dissolution.

Results There was a graded relationship between the number of address changes and mental ill-health (adjusted OR 3.67, 95% CIs 2.11 to 6.39 for 5 or more moves). This relationship was not modified by SES or household composition. Marital dissolution was associated with poor mental health but did not modify the relationship between address change and mental health (p=0.206). There was some indication that movement after the age of five was associated with an increased likelihood of poor mental health.

Conclusions This large study clearly confirms the close relationship between address change in early years and later poor mental health. Residential mobility may be a useful marker for children at risk of poorer mental health in adolescence and early adulthood