Table 2.

Population-environment-development dynamics in selected health problems

	Population	Environment	Development
Waterborne diseases	Rural–urban migration and overcrowded urban centres with poor infrastructure cause overexploitation of water resources, a decline in freshwater availability, intense competition between different uses, and water contamination that in turn leads to increases in the incidence of diarrhoea and other waterborne diseases.^96–99 War-displaced populations live in unhygienic conditions, at high risk of exposure to waterborne diseases¹⁰⁰	Water shortages increase the use of wastewater in irrigation of vegetables, and heavy rain floods the wastewater system and contaminates water supplies in urban areas with poor infrastructure,¹⁰⁰ hence increasing exposure to waterborne pathogens. Climate change creates or exacerbates water supply problems^101,102 and water rationing, which increases exposure to waterborne pathogens in rural and urban areas and reduces food production, leading to more undernutrition, lower immunocompetence, lower resistance to infection and, as a result, more frequent and severe episodes of waterborne diseases^96,103,104	Unplanned urban growth and lack of investment in water networks creates scarce and unreliable water supply services in cities, particularly in informal neighbourhoods, that leads to household measures to conserve water through storage, re-use, and hierarchies of use where hygiene is compromised, which increases exposure to waterborne pathogens.^96,97,105 Ineffectively executed and regulated privatisation policies for piped water provision might lead to lack of coverage in low-income areas, diminishing service quality and increasing prices over time, which jeopardise access to adequate and affordable water by the socioeconomically vulnerable urban populations, increasing their exposure to waterborne diseases^106,107
Undernourishment	Population growth leads to more competition for food and water, more urban encroachment on agricultural land, reduction in available land per person, all contributing to less available and less diverse food, with resultant undernourishment for people with low income⁶⁸	Depleting groundwater reserves and climate change lead to less rainfall, more frequent droughts, and sea-level rise, all of which reduce crops and available food to populations and cause substantial damage to rural livelihoods; the latter leads to faster rural–urban flux, less agricultural land, and more undernourishment in people with low income^69,96,103	Government subsidies for irrigation agriculture lead to long-term depletion of groundwater resources, sea-water intrusion, and high susceptibility of yields, with a resultant decline in availability and diversity of food for growing populations. Urbanisation leads to changes in dietary habits towards more water-intensive animal protein, high dependence on imported food, and susceptibility to price fluctuations, all resulting in more undernourishment for people with low income^66,94
Reproductive health problems	Migration, especially from low-income rural areas to the outskirts of cities and slum areas, is leading to increased urban poverty and low-income urban environments (crowding, pollution, restricted water supply, and bad sanitation). People in developing countries living in urban areas with a low-income have been shown to have less access to reproductive health services and to have more reproductive morbidities than those with higher incomes living in urban areas¹⁰⁸	Pollutants in the environment as a result of war lead to increasing male infertility, which increases out-of-pocket expenditures and interferes with reproductive choice, resulting in worse reproductive health outcomes¹⁰⁹	Shrinking of the public sector and privatisation lead to less employment opportunities for women in the public sector and more employment opportunities in the private and informal sectors, in which salaries and benefits are less secure. This precariousness of women′s employment, especially women from a low-income background, together with women′s decreasing access to services in a privatised health system, lead to less access to reproductive health services and increased likelihood of reproductive health problems^110,111
Occupational health problems	People who have a low income, are unemployed, or are migrant workers often accept work in hazardous occupations with minimal safety standards.¹¹² Child labour increases in overcrowded urban neighbourhoods with poor public schooling systems.¹¹³ Women in rural areas are overburdened with agricultural work in addition to housework and family rearing	Workers in many formal and informal sectors in the Arab world have higher-than-average exposure to climate-related hazards such as heatwaves,¹¹⁴ sea-level rise, and spread of malaria. Outdoor workers (eg, traffic policemen, street sweepers) are at high risk of exposure to increased air pollution from traffic¹¹⁵ and electric generators	Economic restructuring, resource-based development, and free trade agreements create new job opportunities for some (eg, construction workers in some countries bordering the Persian Gulf, women in the service sector) and unemployment for others (eg, labourers in agricultural sectors with low investment); changing employment modalities such as outsourcing, flexible working arrangements, migrant workers with little regulatory protection, low salaries, and job volatility often undermine social protection and lead to the dilution of health and safety regulations⁵⁰
Traffic injuries	Crowded cities with poor public transportation generate traffic congestion, overcrowded buses and trains, and restricted space for pedestrians and bikers, increasing the risk of traffic incidents and injuries. Immigrant children¹¹² and children from low-income backgrounds working in the streets are at high risk of traffic injuries	Adverse weather conditions (rain, dust storms) increase the rate of vehicle crashes¹¹⁶ (eg, flash floods in the Arab peninsula have been associated with traffic fatalities)	Traffic injuries are a leading cause of death in Saudi Arabia and other high-income Gulf countries where extensive highways and high-speed cars increase traffic injury.¹¹⁷ Poor public transportation leads to a greater use of private vehicles and motorcycles, increasing the risk of traffic injuries.¹¹⁸ The mix of residential and commercial districts mostly in proximity to highways increases the risk of traffic injuries (eg, Egypt, Lebanon)