INDIRECT ESTIMATES OF ADULT MORTALITY LEVELS FROM THE NIGERIAN DEMOGRAPHIC AND HEALTH SURVEY DATA USING THE SIBLINGS METHOD

Abstract

The data from census and surveys about mortality estimate are often incomplete and inaccurate in developing countries. Even the respondents may fail to report and often do not know about their siblings who died before or during the few years after their own birth. Estimates of reliable mortality indices are needed to assess the impact of health intervention programmes at population subgroups. This study therefore provides estimates of adult mortality level from the Nigeria demographic and health survey using siblings' method. Data from NDHS (2013) were retrieved for adult mortality estimation. A total of 56307 respondents consisting of 17359 males (age 15-49years) and 38948 females (age 15-49 years) were analysed. The socio-demographic data were summarized using descriptive statistics. Indirect estimate of adult mortality using sibling method was done as data on the survival of brothers is used to estimate the mortality of men and data on the survival of sisters were used to estimate the mortality of women while a periodic cohort life table technique was used to project an estimates for the expectation of life. The sibling method was used to relate the proportion of respondents with living brothers and sisters to measure of survivorship probabilities by means of multiplier whose values depends on the mean age at child bearing. This was obtained by averaging age of respondents who gave birth within a year before the survey date. Abridged life tables were constructed by linking the survivorship probabilities in childhood and adulthood using the two parameters logit system. The estimated survival probabilities show that there were decline in survival probabilities with age for both sexes across the age groups except in age group 15-19 and 20-24 where the survival probabilities remain constant among females. The translated 3 Sq 15 values range from 0.196, as estimated for respondents aged 45-49, to 0.433 for respondents aged 15-19 among male while it ranges from 0.196 at age 45-49 to 0.432 at ages 15-19 among the female. Life expectancy at birth for male and female were 70.31 and 62.30 years respectively. Also, the life expectancy at age 50 for male and female were 26.21 and 25.71 years respectively. There is a need to identify and implement health intervention programmes that will improve the life expectancy, especially among women. Periodic monitoring of adult mortality using sibling method in the reliable survey system is also recommended.