Summary Background The odds ratio (OR) comparing pathogen presence in diarrhoeal cases versus asymptomatic controls is a measure for diarrhoeal disease cause that has been integrated into burden of disease estimates across diverse populations. This study aimed to estimate the OR describing the association between pathogen detection in stool and diarrhoea for 15 common enteropathogens by age group and child mortality setting. Methods We did a systematic review to identify case-control and cohort studies published from Jan 1, 1990, to July 9, 2019, which examined at least one enteropathogen of interest and the outcome diarrhoea. The analytical dataset included data extracted from published articles and supplemented with data from the Global Enteric Multicenter Study and the Malnutrition and Enteric Disease study. Random effects meta-analysis models were fit for each enteropathogen, stratified by age group and child mortality level, and adjusted for pathogen detection method and study design to produce summary ORs describing the association between pathogen detection in stool and diarrhoea. Findings 1964 records were screened and 130 studies (over 88 079 cases or diarrhoea samples and 135 755 controls or non-diarrhoea samples) were available for analysis. Heterogeneity ( I 2 ) in unadjusted models was substantial, ranging from 27·6% to 86·6% across pathogens. In stratified and adjusted models, summary ORs varied by age group and setting, ranging from 0·4 (95% CI 0·2–0·6) for Giardia lamblia to 54·1 (95% CI 7·4–393·5) for Vibrio cholerae . Interpretation Incorporating effect estimates from diverse data sources into diarrhoeal disease cause and burden of disease models is needed to produce more representative estimates. Funding WHO, Bill & Melinda Gates Foundation, and National Institutes of Health.

Background An aim of this study is to introduce a practitioner-friendly behavior model. Few theories of health behavior explicitly take the effect of social norms on behavior into account. Generally, theories that do take social norms into account assume that the effect of social norms on behavior operates through motivation. We use the Fogg Behavior Model (FBM), a behavior model that is new to public health, to explore whether social norms are associated with modern contraceptive use among Nigerian women, and whether they affect behavior through motivation or through ability. In other words, do social norms that discourage contraception lower women’s motivation to use contraception or do they lower women’s ability to use contraception. Methods This study uses data from a cross-sectional household survey of Nigerian women, ages 14–24. The survey collected data on socio-economic and demographic characteristics of women, whether they were sexually experienced, and whether they used contraception. Modern contraceptive use was the outcome of interest for the study. The survey also collected data on social norms around premarital sex and contraceptive use. Multivariate logistic regression was used for the analysis. Results After adjusting for a range of socio-economic and demographic variables, we found that social norms that discourage contraception had a statistically significant negative association with contraceptive use (aOR = 0.90, p < 0.001). The analysis found that the negative association between social norms and contraceptive use remained statistically significant after controlling for motivation but did not remain statistically significant after controlling for ability. Conclusion These findings suggest that social norms may affect contraceptive use in Nigeria through ability rather than motivation. In terms of programmatic implications, these finding suggest that public health interventions may be able to counter the negative effects of social norms that discourage contraceptive use by increasing women’s ability to practice contraception.

Background Estimates of the relative contribution of different pathogens to all-cause diarrhoea mortality are needed to inform global diarrhoea burden models and prioritize interventions. We aimed to investigate and estimate heterogeneity in the case fatality risk (CFR) of different diarrhoeal pathogens. Methods We conducted a systematic review and meta-analysis of studies that reported cases and deaths for 15 enteric pathogens published between 1990 and 2019. The primary outcome was the pathogen-specific CFR stratified by age group, country-specific under-5 mortality rate, setting, study year and rotavirus vaccine introduction status. We developed fixed-effects and multilevel mixed-effects logistic regression models to estimate the pooled CFR overall and for each pathogen, controlling for potential predictors of heterogeneity. Results A total of 416 studies met review criteria and were included in the analysis. The overall crude CFR for all pathogens was 0.65%, but there was considerable heterogeneity between and within studies. The overall CFR estimated from a random-effects model was 0.04% (95% CI: 0.026%–0.062%), whereas the pathogen-specific CFR estimates ranged from 0% to 2.7%. When pathogens were included as predictors of the CFR in the overall model, the highest and lowest odds ratios were found for enteropathogenic Escherichia coli (EPEC) [odds ratio (OR) = 3.0, 95% CI: 1.28–7.07] and rotavirus (OR = 0.23, 95% CI: 0.13–0.39), respectively. Conclusion We provide comprehensive estimates of the CFR across different diarrhoeal pathogens and highlight pathogens for which more studies are needed. The results motivate the need for diarrhoeal interventions and could help prioritize pathogens for vaccine development.

Background: Few theories of health behavior explicitly take the effect of social norms on behavior into account. The ones that do assume that the effect of norms on behavior operates through motivation. We use a behavior model that is new to public health to test whether norms affect behavior through motivation or ability. Methods: This study uses data from a household survey of Nigerian women, ages 14-24. The survey collected data on socio-economic and demographic characteristics of women, whether they were sexually experienced, and whether they used contraception. The survey also collected data on descriptive and injunctive norms around premarital sex and contraceptive use. Multivariate logistic regression was used to test whether the effect of unfavorable social norms on modern contraceptive use operates through motivation or ability. Results: The data was used to construct variables measuring unfavorable social norms, motivation, ability, and modern contraceptive use. After adjusting for a range of socio-economic and demographic variables, we found that unfavorable social norms had a statistically significant negative effect on contraceptive use. The analysis suggests that the effect of unfavorable social norms on contraceptive use operates through ability.Conclusion: This study sheds light on the pathway through which social norms affect contraceptive use. The findings suggest that public health interventions may be able to counter the negative effects of unfavorable social norms on modern contraceptive use by increasing women’s ability to practice contraception. These findings have important implications for the design of interventions that aim to increase contraceptive use among young women in Nigeria. The study also demonstrates the utility of the FBM, a practitioner-friendly, behavior change model, in examining the relationship between norms and behavior.