Everyday, Scientist Live turns its eyes to the Web around it and highlights news and research across the Internet. Today we look take an extended look at morbidity and mortality.
SUBSTANCE ABUSE
Alcohol, tobacco, and illegal drug use cause considerable morbidity and mortality, but good cross-national epidemiological data are limited. This paper describes such data from the first 17 countries participating in the World Health Organization's (WHO's) World Mental Health (WMH) Survey Initiative.
Household surveys with a combined sample size of 85,052 were carried out in the Americas (Colombia, Mexico, United States), Europe (Belgium, France, Germany, Italy, Netherlands, Spain, Ukraine), Middle East and Africa (Israel, Lebanon, Nigeria, South Africa), Asia (Japan, People's Republic of China), and Oceania (New Zealand). The WHO Composite International Diagnostic Interview (CIDI) was used to assess the prevalence and correlates of a wide variety of mental and substance disorders. This paper focuses on lifetime use and age of initiation of tobacco, alcohol, cannabis, and cocaine. Alcohol had been used by most in the Americas, Europe, Japan, and New Zealand, with smaller proportions in the Middle East, Africa, and China. Cannabis use in the US and New Zealand (both 42%) was far higher than in any other country. The US was also an outlier in cocaine use (16%). Males were more likely than females to have used drugs; and a sex-cohort interaction was observed, whereby not only were younger cohorts more likely to use all drugs, but the male-female gap was closing in more recent cohorts. The period of risk for drug initiation also appears to be lengthening longer into adulthood among more recent cohorts. Associations with sociodemographic variables were consistent across countries, as were the curves of incidence of lifetime use.
Globally, drug use is not distributed evenly and is not simply related to drug policy, since countries with stringent user-level illegal drug policies did not have lower levels of use than countries with liberal ones. Sex differences were consistently documented, but are decreasing in more recent cohorts, who also have higher levels of illegal drug use and extensions in the period of risk for initiation.
- "Toward a Global View of Alcohol, Tobacco, Cannabis, and Cocaine Use: Findings from the WHO World Mental Health Surveys" Degenhardt L, Chiu WT, Sampson N, Kessler RC, Anthony JC, et al. (2008) Toward a Global View of Alcohol, Tobacco, Cannabis, and Cocaine Use: Findings from the WHO World Mental Health Surveys. PLoS Med 5(7): e141 doi:10.1371/journal.pmed.0050141
MEDICAL
The mechanisms of immune protection against human TB, a disease that causes 2 million deaths world-wide each year, are not fully known. T cell immunity is critical for protection; therefore, the current TB vaccine, bacille Calmette-Guérin (BCG), and most new vaccines under development aim to induce this immunity. Most of these developmental vaccines are designed to boost pre-existing immunity induced by BCG; however, some candidates aim to ultimately replace BCG as the priming vaccine. Following phase I/IIa trials of the vaccines, safety and immunogenicity results will be critical to decide which vaccine candidates should move into efficacy trials. For this choice, the ability to compare immunogenicity would be an important asset. Potential comparisons are confounded by variation in individual laboratory approaches, logistics, and the diverse populations studied in vaccine trials. Some comparison may be achieved by harmonisation of assays (see below); however, even then, antigen components of vaccines and therefore antigens in assays may differ. Further, the desired character of induced immunity may differ according to vaccine candidate, making choice of an assay to be harmonised difficult.
To tackle this problem, the WHO Initiative for Vaccine Research sponsored three meetings of experts representing current TB vaccine development efforts to discuss the requirements for and challenges in harmonising assays for new TB vaccine trials. The primary focus was on phase I and IIa trials; other principles may apply to phase IIb and III trials because of their larger sample sizes and because resources in settings of these trials may differ. In this article, we describe advantages and disadvantages of multiple assay approaches and make recommendations for using specific assay approaches in phase I/IIa trials.
- "Immunological Outcomes of New Tuberculosis Vaccine Trials: WHO Panel Recommendations" Hanekom WA, Dockrell HM, Ottenhoff THM, Doherty TM, Fletcher H, et al. (2008) Immunological Outcomes of New Tuberculosis Vaccine Trials: WHO Panel Recommendations. PLoS Med 5(7): e145 doi:10.1371/journal.pmed.0050145
MORBIDITY/MORTALITY
The effects of crises (man-made or natural disasters) on physical health are ultimately quantifiable as a rise in mortality. Precise and unbiased estimates of mortality rates (deaths per person-time) or excess death tolls (deaths attributable to the presence of the crisis) are critical to grading the severity of a crisis at its onset and over time, and adjusting relief operations accordingly [1,2]. Indeed, the onset of emergencies is commonly defined as a doubling of mortality rate from the pre-crisis baseline, or the crossing of fixed thresholds, typically one death per 10,000 person-days [2]. In reality, because mortality increases only after a crisis has evolved, acute malnutrition may be a better indicator for early crisis detection [3], and data on morbidity and on the coverage of interventions against the main known risk factors for poor health outcomes (e.g., insufficient water and sanitation, lack of preventive and curative health services, etc.) are more useful to target relief programmes and minimise preventable deaths.
Mortality data also provide a basis for advocacy, which may be "humanitarian" (calling for appropriate assistance) or "political" (for example, calling for compliance with international humanitarian law [IHL], a set of rules that seek to limit the effects of armed conflict for humanitarian reasons [see http://www.icrc.org/web/eng/siteeng0.nsf/html/humanitarian-law-factsheet]). As historical documents, mortality data also illuminate the consequences of humanity's failures to resolve conflicts non-violently and to protect vulnerable groups from war or disasters. In Table 1, we outline these two main functions of mortality data-the support of relief operations and evidence-building for advocacy/documentation. However, we believe that both functions can often be served simultaneously. In this article, we attempt to summarise how mortality within crisis-affected populations is documented at present, discuss our perceptions of the barriers to better mortality measurement, and suggest ways by which these barriers might be overcome.
- "Documenting Mortality in Crises: What Keeps Us from Doing Better?" Checchi F, Roberts L (2008) Documenting Mortality in Crises: What Keeps Us from Doing Better? PLoS Med 5(7): e146 doi:10.1371/journal.pmed.0050146
