Population Scenarios and Policy Implications for Southern Mediterranean Countries, 2010-2050. MEDPRO Policy Paper No. 5, March 2013

Four population scenarios were derived that describe indicators of demographic behaviour for people living in different future political-economic contexts. This policy paper explores future trends in i) population growth at regional and national levels, ii) working age populations, in view of demographic dividend potential, and iii) elderly populations, in view of the financial burden they place on economies. Results show that different scenarios do not have large effects on population growth, at least up to 2030. This is due to the in-built ‘population momentum’ effect in the relatively young age-structures of most southern and eastern Mediterranean countries (SEMCs). In the short term, up to 2030, and depending on which economic-political scenario unfolds, SEMCs are expected to grow from 280 million people to a figure of between 362 and 349 million people. Thus, in a period of about 20 years SEMCs are expected to grow by between 69 and 83 million people. In the same period, EU27 populations will grow by 21 million; only from about 500 to 521 million people. Between 2030 and 2050, additional population growth is foreseen in SEMCs, between 48 and 62 million people, while EU27 populations are expected to grow by 4 million only. SEMCs vary widely regarding demographic transition profiles so that demographic dividend potentials also vary. Old-age dependency ratios – the share of elderly people in relation to the working age population – are still low compared to EU27 ratios, but will increase after 2035. Should SEMCs’ economies remain politically, economically and environmentally precarious in the coming decades, their relatively low dependency ratios may impose an even higher social and financial burden on economies than the EU countries’ high dependency ratios impose on their economies.

Control of structured populations by harvest

It has long been recognized that demographic structure within a population can significantly affect the likely outcomes of harvest. Many studies have focussed on equilibrium dynamics and maximization of the value of the harvest taken. However, in some cases the management objective is to maintain the population at a abundance that is significantly below the carrying capacity. Achieving such an objective by harvest can be complicated by the presence of significant structure (age or stage) in the target population. in such cases, optimal harvest strategies must account for differences among age- or stage-classes of individuals in their relative contribution to the demography of the population. In addition, structured populations are also characterized by transient non-linear dynamics following perturbation, such that even under an equilibrium harvest, the population may exhibit significant momentum, increasing or decreasing before cessation of growth. Using simple linear time-invariant models, we show that if harvest levels are set dynamically (e.g., annually) then transient effects can be as or more important than equilibrium outcomes. We show that appropriate harvest rates can be complicated by uncertainty about the demographic structure of the population, or limited control over the structure of the harvest taken. (c) 2006 Elsevier B.V. All rights reserved.

Reducing the global burden of depression : population level analysis of intervention cost-effectiveness in 14 world regions

International evidence on the cost and effects of interventions for reducing the global burden of depression remain scarce. Aims: To estimate the population-level cost-effectiveness of evidence-based depression interventions and their contribution towards reducing current burden. Method: Primary-care-based depression interventions were modelled at the level of whole populations in 14 epidemiological subregions of the world. Total population-level costs (in international dollars or I$) and effectiveness (disability adjusted life years (DALYs) averted) were combined to form average and incremental cost-effectiveness ratios. Results: Evaluated interventions have the potential to reduce the current burden of depression by 10–30%. Pharmacotherapy with older antidepressant drugs, with or without proactive collaborative care, are currently more cost-effective strategies than those using newer antidepressants, particularly in lower-income subregions. Conclusions: Even in resource-poor regions, each DALYaverted by efficient depression treatments in primary care costs less than 1 year of average per capita income, making such interventions a cost-effective use of health resources. However, current levels of burden can only be reduced significantlyif there is a substantialincrease substantial increase intreatment coverage.