Adolescent health epidemiology
In 2004 2.6 million young people died (10-24 years) and most of these deaths were preventable. Ninety-seven percent of these deaths (2.56 million), occurred in low- and middle-income countries. Death rates rose sharply from early adolescence (10-14 years) to young adulthood (20-24 years), the causes varied by region and sex. Over the last 50 years, mortality rates in all age groups from children to adolescents and young adults, have declined. However, mortality among young people (15-24 years) has decreased less than for these other age groups, overtaking childhood mortality in high income countries.
Where mortality occurs
Almost two thirds of the 2.6 million deaths among young people were in sub-Saharan Africa and southeast Asia, (1.67 million). Pronounced rises in mortality rates were recorded from early adolescence (10–14 years) to young adulthood (20–24 years), but reasons varied by region and sex.
Causes of adolescent mortality
- 15% of female deaths were caused by maternal conditions
- 11% of deaths were due to HIV/AIDS and tuberculosis
- 14% of male and 5% of female deaths resulted from traffic accidents
- 12% of male deaths resulted from violence
- 6% of all deaths resulted from suicide.
Disability adjusted life years (DALY)
The total number of incident DALYs in those aged 10–24 years was about 236 million, representing 15.5% of total DALYs for all age groups. Africa had the highest rate of DALYs for this age group, which was 2.5 times greater than in high-income countries (208 vs 82 DALYs per 1000 population). Across regions, DALY rates were 12% higher in girls than in boys between 15 and 19 years (153 vs. 137 ). Worldwide, the three main causes of YLDs for 10–24-year-olds were neuropsychiatric disorders (45%), unintentional injuries (12%), and infectious and parasitic diseases (10%).
The main risk factors for DALYs in 10–24-year-olds were:
- alcohol (7% of DALYs)
- unsafe sex (4%)
- iron deficiency (3%)
- lack of contraception (2%)
- illicit drug use (2%)
In younger adolescents, the more typical risk factors for children continued to be more prevalent, in addition to iron deficiency, namely unsafe water, sanitation and hygiene.
The epidemiological analyses presented here now have an improved empirical base for assessing the disease burden. However, there are still substantial data gaps and uncertainties particularly for causes of death and levels of adolescent and adult mortality in Africa and parts of Asia. Thus improvements in population-level information about causes of death and the incidence, prevalence, and health states that are associated with causes of major disease and injury are still a main priority for national and international health and statistical agencies.
Better information on young people than is currently available will require improved health-information systems, notably in efforts towards improving death registration data as well as that obtained through household surveys and research studies. Such data systems and surveys should report results for more detailed age categories that are relevant to young people, rather than broad age-classifications as is currently the case.