Biomedical subjects

Ajay Tandon

Publications and source records attributed to Ajay Tandon.

6 recordsLinked to original sources

PubMed2005

From wealth to health: modelling the distribution of income per capita at the sub-national level using night-time light imagery.

BACKGROUND: Sub-national figures providing information about the wealth of the population are useful in defining the spatial distribution of both economic activity and poverty within any given country. Furthermore, since several health indicators such as life expectancy are highly correlated with household welfare, sub-national figures allow for the estimation of the distribution of these health indicators within countries when direct measurement is difficult.We have developed methods that utilize spatially distributed information, including night-time light imagery and population to model the distribution of income per capita, as a proxy for wealth, at the country and sub-national level to support the estimation of the distribution of correlated health indicators. RESULTS: A first set of analysis are performed in order to propose a new global model for the prediction of income per capita at the country level. A second set of analysis is then confirming the possibility to transfer the country level approach to the sub-national level on a country by country basis before underlining the difficulties to create a global or regional models for the extrapolation of sub-national figures when no country data set exists. CONCLUSIONS: The methods described provide promising results for the extrapolation of national and sub-national income per capita figures. These results are then discussed in order to evaluate if the proposed methods could not represent an alternative approach for the generation of consistent country specific and/or global poverty maps disaggregated to some sub-national level.

Journal Article↗

PubMed2005

Access, utilization, quality, and effective coverage: an integrated conceptual framework and measurement strategy.

Health systems can primarily improve the health of individuals and populations by delivering high-quality interventions to those who may benefit from them. We propose a concept of effective coverage as the probability that individuals will receive health gain from an intervention if they need it. Understanding the extent to which health systems are delivering key interventions to those who will benefit from them and the factors that explain gaps in delivery are a critical input to decision-making at the local, national and global levels. We develop an integrated conceptual framework for monitoring and analyzing the delivery of high-quality interventions to those who need them. This framework can help clarify the inter-relationships between notions of access, demand for care, utilization, and coverage on the one hand and highlight the requirements for health information systems that can sustain this type of analysis. We discuss measurement strategies and demonstrate the concept by means of a simple simulation model.

Asthma↗

PubMed2004

Global patterns of healthy life expectancy in the year 2002.

BACKGROUND: Healthy life expectancy--sometimes called health-adjusted life expectancy (HALE)--is a form of health expectancy indicator that extends measures of life expectancy to account for the distribution of health states in the population. The World Health Organization reports on healthy life expectancy for 192 WHO Member States. This paper describes variation in average levels of population health across these countries and by sex for the year 2002. METHODS: Mortality was analysed for 192 countries and disability from 135 causes assessed for 17 regions of the world. Health surveys in 61 countries were analyzed using new methods to improve the comparability of self-report data. RESULTS: Healthy life expectancy at birth ranged from 40 years for males in Africa to over 70 years for females in developed countries in 2002. The equivalent "lost" healthy years ranged from 15% of total life expectancy at birth in Africa to 8-9% in developed countries. CONCLUSION: People living in poor countries not only face lower life expectancies than those in richer countries but also live a higher proportion of their lives in poor health.

Cross-Cultural Comparison↗

PubMed2004

Comparability of self rated health: cross sectional multi-country survey using anchoring vignettes.

OBJECTIVE: To examine differences in expectations for health using anchoring vignettes, which describe fixed levels of health on dimensions such as mobility. DESIGN: Cross sectional survey of adults living in the community. SETTING: China, Myanmar, Sri Lanka, Pakistan, Turkey, and United Arab Emirates. PARTICIPANTS: 3012 men and women aged 18 years and older (self ratings); subsample of 406 (vignette ratings). MAIN OUTCOME MEASURES: Self rated mobility levels and ratings of hypothetical vignettes using the same questions and response categories. RESULTS: Consistent rankings of vignettes are evidence that vignettes are understood in similar ways in different settings, and internal consistency of orderings on two mobility questions indicates good comprehension. Variation in vignette ratings across age groups suggests that expectations for mobility decline with age. Comparison of responses to two different mobility questions supports the assumption that individual ratings of hypothetical vignettes relate to expectations for health in similar ways as self assessments. CONCLUSIONS: Anchoring vignettes could provide a powerful tool for understanding and adjusting for the influence of different health expectations on self ratings of health. Incorporating anchoring vignettes in surveys can improve the comparability of self reported measures.

Adolescent↗

PubMed2003

Validity of reported vaccination coverage in 45 countries.

BACKGROUND: Monitoring and assessment of coverage rates in national health programmes is becoming increasingly important. We aimed to assess the accuracy of officially reported coverage rates of vaccination with diphtheria-tetanus-pertussis vaccine (DTP3), which is commonly used to monitor child health interventions. METHODS: We compared officially reported national data for DTP3 coverage with those from the household Demographic and Health Surveys (DHS) in 45 countries between 1990 and 2000. We adjusted survey data to reflect the number of valid vaccinations (ie, those administered in accordance with the schedule recommended by WHO) using a probit model with sample selection. The model predicted the probability of valid vaccinations for children, including those without documented vaccinations, after correcting for bias from differences between the children with and without documented information on vaccination. We then assessed the extent of survey bias and differences between officially reported data and those from DHS estimates. FINDINGS: Our results suggest that officially reported DTP3 coverage is higher than that reported from household surveys. This size of the difference increases with the rate of reported coverage of DTP3. Results of time-trend analysis show that changes in reported coverage are not correlated with changes reported from household surveys. INTERPRETATION: Although reported data might be the most widely available information for assessment of vaccination coverage, their validity for measuring changes in coverage over time is highly questionable. Household surveys can be used to validate data collected by service providers. Strategies for measurement of the coverage of all health interventions should be grounded in careful assessments of the validity of data derived from various sources.

Child↗

PubMed2003

Healthy life expectancy: comparison of OECD countries in 2001.

OBJECTIVES: To compare average levels of population health for Australia and other OECD countries in 2001. METHODS: Healthy life expectancies (HALE) for OECD countries for 2001 are based on analysis of mortality data for OECD countries, country-specific estimates of health state prevalences for 135 causes from the Global Burden of Disease 2000 study, and an analysis of 34 health surveys in 28 OECD countries, using novel methods to improve the comparability of self-report data. RESULTS: HALE at birth ranges from a low of 59.8 years for Turkey to a high of 73.6 years in Japan in 2001. Australia ranks fourth among OECD countries at 71.6 years with a 95% uncertainty interval of 70.9 to 72.8 years, ahead of New Zealand in 13th place at 70.3 years. The equivalent 'lost' healthy years at birth range from around 10 years in OECD countries with lowest life expectancies to around eight years in those with high life expectancies at birth. There is a statistically significant association between higher levels of health expenditure and higher healthy life expectancy across OECD countries, although causal inferences require more sophisticated analyses of the health system and non-health system determinants of levels of health. CONCLUSIONS: The new methods used in the WHO Multi-Country Household Survey Study have increased the comparability of self-report data across OECD countries, a major step forward in the use of self-reported data on health. Building on this experience, WHO is developing improved health status measurement techniques for a World Health Survey to be carried out in 2002/03.

Aged↗