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Environmental factors

Giuseppe Leontino

Figure 3.1 Long-term conditions in numbers. England.

Table 3.1 Long-term conditions and main risk factors.

Source: Available from https://www.sciencedirect.com/science/article/pii/S2214999616000059#appsec1

• Tobacco smoke
• Ambient/household air pollution
• Ecological exposure to PCBs

• Tobacco smoke
• Ambient/household air pollution
• Ecological exposure to PCBs
• POPs
• Gastrointestinal dysbiosis

• Ambient air pollution
• Arsenic
• POPs

• Tobacco smoke
• POPs
• Ambient air pollution
• Household air pollution
• Ambient noise

• POPs
• Bisphenol A/phthalates
• Ambient air pollution

• Tobacco smoke
• POPs
• Ambient air pollution
• Arsenic (drinking water)

• Heavy metals
• Air pollution
• Herbicides

Figure 3.2 Prevalence of long-term conditions in England. AF, atrial fibrillation; HF, heart failure; HYP, hypertension; STIA, stroke and ischaemic attack; CHD, coronary heart disease; COPD, chronic obstructive pulmonary disease; AST, asthma; CAN, cancer; CKD, chronic kidney disease; DM, diabetes mellitus; DEM, dementia; DEP, depression; EP, epilepsy; LD, learning disability; MH, mental health; OST, osteoporosis; RA, rheumatoid arthritis.

Long-term conditions (LTCs) are chronic health conditions that do not have a cure but that can be managed by medications or other therapies. Figure 3.1 gives a snapshot of the current situation in England whilst Figure 3.2 provides an insight around prevalence of LTCs.

The World Health Organization (WHO) produced evidence that ascribed 24% of the global disease and 23% of all deaths to long-term environmental exposures in adults, and up to 36% in children aged 0-14?years old.

The environment is made of different elements that contribute to improving and diminishing people's health depending on accessibility to:

• clean air and water
• transportation
• green spaces and cycle lanes
• wellness facilities.

Environmental health is concerned with elements of the environment that are directly affected by human activities like man-made structures, and those linked to the intrinsic meaning of nature itself like geography. Geographical characteristics influence the climate and the resources available to people. For instance, direct sunlight exposure promotes healthy levels of vitamin D. In the United Kingdom (UK) 34% of men and 33% of women have been found to be deficient in this rather life-essential hormone. In fact, the UK has lower overall vitamin D status compared to Western Europe. Levels of vitamin D?<?25?nmol/l can lead to:

• rickets
• osteomalacia
• osteoporosis.

The recommended levels of vitamin D of more than 50?nmol/l can be maintained by fortifying foods like wheat flour or supplementation:

• 8.5-10?µg of vitamin D a day for babies up to the age of one?years old
• 10?µg of vitamin D a day for children from the age of one?years old and adults.

Physical factors

LTCs may originate from an inflammatory response mechanism derived from consistent and prolonged exposure to toxins present in all aspects of the physical environment:

• soil
• aquatic
• atmospheric
• built ecosystems.

These toxins originate from a plethora of sources such as:

• vehicles and fuels
• Industries and factories.

Some of the pollutants currently identified as highly injurious to health are:

• tobacco smoke
• traffic-related pollutants
• polycyclic aromatic hydrocarbons
• endocrine-disrupting chemicals
• heavy metals
• UV and ionising radiations
• dioxins, furans
• bioaerosols
• phytoestrogens
• tributyltin (TBT)
• bisphenol A (BPA)
• diethylstilbesterol (DES).

The effects of long-term exposure even at low dosage to these pollutants may lead to a variety of conditions as shown in Table 3.1.

Studies addressing the ever-growing rate of metabolic diseases suggest that these are not solely caused by:

• food choices
• genetic predisposition
• physical exercise.

There is strong evidence to suggest that air pollutants and endocrine disrupting chemicals could be linked to metabolic disorders such as diabetes and obesity. The mechanisms of action are multiple:

• lipid and glucose metabolism
• endothelium inflammation
• altering homeostatic metabolic set-points
• disrupting appetite controls
• direct binding to nuclear receptors acting as agonists or antagonists
• enzymatic activity inhibition.

Areas with high levels of small particulate matter (PM 2.5) have been linked to a worsening of symptoms in people who suffer from respiratory disorders, resulting in increased hospital admissions and about 5% of total mortality in England. PM 2.5 and nitrogen dioxide (NO2) together account for a health annual cost of around £22.6?billion. The exposure to these toxins has been reduced by 44% and 56% respectively between 1970 and 2010.

After air pollutants, noises have been classified as the second largest environmental toxin in Western Europe. Noise pollution has been determined to be more detrimental to health than lead, ozone, and dioxins. The main source of noise pollution is road traffic which affects 11.5?million in England.

Noise pollution has been linked to:

• severe chronic annoyance
• coronary heart disease
• metabolic conditions, such as diabetes and obesity
• disruption to children's learning and development.

Sleep disturbance promotes long-term consequences in healthy individuals by affecting the:

• sympathetic nervous system
• hypothalamic-pituitary-adrenal axis
• metabolic syndrome
• changes in circadian rhythms
• proinflammatory responses.

These effects can in the long term lead to:

• hypertension
• dyslipidaemia
• cardiovascular disease
• weight-related issues
• metabolic syndrome
• type 2 diabetes mellitus
• colorectal cancer.

One study has estimated the medical cost of noise-related hypertension and associated conditions in the UK at £1.09?billion a year. The findings suggested that exposure to noise above recommended levels resulted in an extra:

• 1169 cases of dementia
• 788 strokes
• 542 heart attacks.

The total social cost of road traffic noise pollution, including health costs, productivity losses and chronic severe annoyance, has been estimated to be more than £9?billion annually.

Psycho-social factors

The social environment can be as harmful as air pollution. Psycho-social factors are responsible for inducing mental health disorders as well as physical health conditions.

The social environment includes factors such as:

• safety
• occupation
• criminal activity and violence
• social connections
• social participation
• social cohesion
• social capital.

Mental health disorders have been linked to increased levels of stress that derives from:

• safety
• social disorders
• social participation
• integration.

Conversely, the quality of social connections and social support may improve health by increasing resilience which buffers the adverse effect of stress.

Occupational and socioeconomic risk factors have been investigated for the potential to develop and promote:

• inadequate physical activity
• drug and alcohol use
• labour-intense occupation
• exposure to dusts, silica, and other air pollutants.

Studies have reported the connection between self-reported health status and social capital which is defined as 'the network of relationships amongst individuals who live and work in a society, enabling that society to function effectively.' Furthermore, social capital interventions can endorse mental health well-being and prevent common mental health disorders (CMD) such as:

• depression
• generalised anxiety disorder (GAD)
• panic disorder
• phobias
• social anxiety disorder
• obsessive-compulsive disorder (OCD)
• post-traumatic stress disorder (PTSD).

Conclusions

Environmental exposure and behavioural risk factors...