Measuring and modelling concurrency

This article explores three critical topics discussed in the recent debate over concurrency (overlapping sexual partnerships): measurement of the prevalence of concurrency, mathematical modelling of concurrency and HIV epidemic dynamics, and measuring the correlation between HIV and concurrency. The focus of the article is the concurrency hypothesis – the proposition that presumed high prevalence of concurrency explains sub-Saharan Africa's exceptionally high HIV prevalence. Recent surveys using improved questionnaire design show reported concurrency ranging from 0.8% to 7.6% in the region. Even after adjusting for plausible levels of reporting errors, appropriately parameterized sexual network models of HIV epidemics do not generate sustainable epidemic trajectories (avoid epidemic extinction) at levels of concurrency found in recent surveys in sub-Saharan Africa. Efforts to support the concurrency hypothesis with a statistical correlation between HIV incidence and concurrency prevalence are not yet successful. Two decades of efforts to find evidence in support of the concurrency hypothesis have failed to build a convincing case

Comparison of two sources of iodine delivery on breast milk iodine and maternal and infant urinary iodine concentrations in southern Ethiopia: A randomized trial

Iodine deficiency during pregnancy and lactation could expose the infant to severe iodine deficiency disorders. A randomized supplementation trial among rural lactating women was conducted in Sidama zone, southern Ethiopia, to compare the methods of iodine delivery on breast milk iodine, and on maternal and infant urinary iodine concentrations. Women were randomly assigned either to receive 225 μg iodine as potassium iodide capsule daily for 6 months or 450 g of appropriately iodized salt (30–40 μg I as KIO3/g of salt) weekly for household consumption for 6 months. Breast milk iodine concentration (BMIC) and maternal and infant urinary iodine concentration (UIC) were measured at baseline and at 6 months. The women did not differ in BMIC and UIC, and infants did not differ in UIC in a time by treatment interaction. Median (IQR, interquartile range, IQR) BMIC at baseline was 154 [43, 252] μg/L and at 6 months was 105 [36, 198] μg/L, maternal UIC at baseline was 107 [71, 161] μg/L and at 6 months was 130 [80, 208] μg/L; infant UIC at baseline was 218 [108, 356] μg/L and at 6 months was 222 [117, 369] μg/L. Significant correlations among the three variables were obtained in both groups at both times. We conclude that for lactating women an adequate amount of appropriately iodized salt (30–40 μg I/g) had similar effects as a daily supplement of 225 μg I on BMIC and on maternal and infant UIC

Quantifying user preferences for sanitation construction and use: Application of discrete choice experiments in Amhara, Ethiopia.

OBJECTIVE: To quantify stated preferences for latrine use and construction in Amhara, Ethiopia, using Discrete Choice Experiments (DCEs). METHODS: We conducted image-based DCEs to assess preferences for latrine use (stratified by gender) and construction (among men only) in Amhara, Ethiopia. Preference was quantified using a conditional logistic model to estimate utilities and corresponding odds ratios associated with a set of latrine attributes. RESULTS: For latrine use, tin roof, handwashing stations and clean latrines had the highest relative utility coefficients. Tin roof was preferred to no roof for use (Women: OR: 3.68, 95% CI: 3.18-4.25; Men: OR: 3.75, 95% CI: 3.21-4.39) and new latrine construction (5.92, 5.04-6.95). Concrete slabs, a critical aspect of improved sanitation, was not preferred to dirt floors for use (Women: 0.87, 0.75-1.00; Men: 1.03, 0.88-1.20), but was preferred for new construction (1.52, 1.30-1.78). We did not observe any trends in preference for direct (monetary) or indirect cost (labour days), so we were not able to elicit trade-offs between latrine attributes and these costs for the construction of new latrines. CONCLUSION: Our findings suggest similar latrine use preferences between men and women. We found that tin roofs are the most strongly preferred latrine characteristic, but concrete slabs, commonly promoted in sanitation programmes, were not preferred for use. We demonstrate the utility of DCEs to elicit stated preferences for latrine use and construction among community members who have myriad motivations for using and making improvements to their sanitation facilities, including the ease of cleaning and hygiene, durability, or privacy and comfort