The biggest investment that any country makes in children and young people is in education. It's also one of the most important investments in international development. With wide ranging benefits, in terms of later quality of life, labor force, skills, economic productivity, and their capacity to parent the next generation. It also has profound effects on health, both during the adolescent years, but also in later life. The major educational focus in the millennium development goals, or the MDGs, which you may recall from discussion earlier this week, was on the primary school years. Yet there has been substantial progress in school attendance across the adolescent and secondary school years. Across the globe, rates of school attendance in younger adolescents have generally increased, but the progress has been uneven. This graph is from UNESCO data. And, illustrates trends over the twelve years from the turn of the millennium in the number of younger adolescents, aged ten to 14, who are not attending school. There are marked differences between regions. Despite retention in primary school being a millennium development goal, and education of girls an international development priority, the number of adolescents out of school in sub-Saharan Africa has changed little during this time. In contrast, in south and west Asia, there's been substantial progress with rates of girls out of school. More than 40% lower in little more than a decade. In other low and middle income countries, progress has been exceptional. With rates of younger adolescents out of school falling to well under half of what they were over the same period of time. So, I've said that education matters for health in many ways. But, how does this come about? Why is it that these young people pictured here are likely to have better health than young people not in school? Not only during the adolescent years, but all the way through life. There are a range of mechanisms that we think are important. Those who have been through school have better access to health information, and also to knowledge and skills to access that information around health later in life. Those who have been to school are likely to have better employment prospects. Unemployment has disastrous effects on health. And, these young people are likely to get better jobs, that carry fewer health risks then those that did not have the opportunities for secondary education. Those who have been through education have both a different peer group, and different marriage prospects. This is also likely to be important in terms of health, and health related behaviours. And, we'll talk more about that in a later lecture. Lastly, those who've been through schools have in many places better earning prospects. Income buys access to health care, that the poor may not be able to afford. In summary, all of these factors lead not only to different attitudes to health, but greater access to resources that underpin health. Differences in educational attainment is a factor underlying the differences in non-communicable diseases, such as cancer and cardiovascular disease later in life. Tobacco use is an example of a health risk that for the great majority arises during adolescence. The association between educational attainment and tobacco use in adulthood is evident in this figure. Those who reach higher levels of education are less likely to start in the first place, and they're more likely to have the resources to quit if they had been smokers. The association between the rate of young adolescent girls who are out of school, and the adolescent birth rate is also very clear. It's clear in every region. In the high income countries, shown here in blue of western Europe, adolescent birth rates are low. But still, there is an association with the proportion of girls who are out of school. In the Asian countries shown here in green, there's almost a linear association between teenage fertility and rates of girls out of school. And, as we've seen, in Sub-Saharan Africa, the region with the highest teenage fertility rates, again, we see an almost linear relationship, with the highest rates of teenage birth. In those countries where you have the highest rates of girls out of school. Being out of school is associated not just with early pregnancy and early marriage, but also with engagement in occupations and illegal activities that further risk health and well-being. It might be a young sex worker who is at risk of sexually transmitted infection, HIV, substance abuse, mental health problems. There are further risks that come from being in juvenile detention. For young males, it might be a young male that's dropped out of school and engaged in the illicit drug industry, and is at risk of violence and drug addiction. These are the kinds of risky occupations that are the only alternative, commonly, for an adolescent who does not have the opportunity to continue in school. And, they have profound effects on health. This slide shows the changes that we've seen in global youth unemployment since the time of the global financial crisis in 2007. At the time, you found employment grew sharply. One of the reasons being, that during times of recession, it's a case of last in, first out. And, that's young people who are most vulnerable. And, unemployment matters for the health of young people in a range of ways. Just as for eduction, employment brings knowledge and skills that underpin health. It influences the peer group that a young person mixes with. And, it also influences the income a young person receives, and in turn, access to health resources, including health insurance. That impact on access to health care was recently illustrated in a global financial crisis in Greece. Where, not only did self reported health decline, but unmet need for health and dental care increased. And, it is the young unemployed who are the most vulnerable in these circumstances. Conversely, making a successful transition to employment after finishing education, is another step in securing, not only, health in young adulthood but, health across the rest of life.