Luchtvervuiling geeft hoge kans op diabetes en slecht voor hart*
Regelmatig blootgesteld zijn aan luchtvervuiling geeft een duidelijk hogere kans op diabetes en het krijgen van hartproblemen zoals een hartaanval een beroerte of hartfalen, zo blijkt uit twee studies. Vooral ouderen en hartpatiënten kunnen volgens de eerste studie beter luchtvervuiling zoveel mogelijk vermijden. Vooral fijnstof met een aerodynamische diameter kleiner dan 2,5 micrometer (PM2,5)
richt de meeste schade aan. Deze fractie wordt voor een groot deel veroorzaakt door wegverkeer. Uit de tweede studie, waarbij 1.775 vrouwen zestien jaar lang gevolgd werden, blijkt dat zij die binnen 100 meter van een drukke weg wonen tot wel twee keer meer kans op diabetes type-2 hebben.
Exposure to fine particulate matter can trigger cardiovascular deaths, heart attacks
Air pollution is a risk factor for heart disease; however people can take action to reduce their individual risk
Exposure to fine particulate matter over a few hours or weeks can trigger cardiovascular deaths, heart attacks, strokes, heart failure and irregular heartbeats, especially in susceptible individuals
Long-term exposure to elevated concentrations of fine particulate matter even further increases cardiovascular risk and reduces life expectancy probably by several months to a few years for those with higher exposures
The scientific evidence linking air pollution to heart attacks, strokes and cardiovascular death has "substantially strengthened," and people, particularly those at high cardiovascular risk, should limit their exposure, according to an updated American Heart Association scientific statement. The evidence is strongest for fine particulate matter (PM2.5) having a causal relationship to cardiovascular disease, said the expert panel of authors who updated the association's 2004 initial statement on air pollution, also published in Circulation: Journal of the American Heart Association.
The major source of PM2.5 is fossil fuel combustion from industry, traffic, and power generation. Biomass burning, heating, cooking, indoor activities and forest fires may also be relevant sources, particularly in certain regions.
"Particulate matter appears to directly increase risk by triggering events in susceptible individuals within hours to days of an increased level of exposure, even among those who otherwise may have been healthy for years," said Robert D. Brook, M.D., lead author of the statement, which was written after review of epidemiological, molecular and toxicological studies published during the past six years.
"Growing evidence also shows that longer-term PM2.5 exposures, such as over a few years, can lead to an even larger increase in these health risks. In this context, the American Heart Association said that PM2.5 should be recognized as a 'modifiable factor' that contributes to cardiovascular morbidity and mortality."
In the statement, the panel also concluded that there's a:
· "small yet consistent" association between short-term exposure to air pollution and pre-mature death;
· strong level of evidence supporting a relationship between air pollution and ischemic heart disease;
· "moderate, yet growing link" between air pollution and heart failure and ischemic stroke;
· "modest" level of evidence supporting an association between air pollution and peripheral vascular diseases, irregular heartbeats and cardiac arrest.
The elderly and those with existing heart diseases, such as heart failure or coronary artery disease, and perhaps those with diabetes appear to be at higher risk from short-term PM2.5 exposure.
"The foremost message for these high-risk groups remains that they should work to control their modifiable traditional risk factors – blood pressure, cholesterol, diabetes, smoking," said Brook, a cardiovascular medicine specialist and associate professor in the Department of Internal Medicine at the University of Michigan in Ann Arbor.
There are several ways by which PM2.5 could affect the cardiovascular system; however, one leading explanation suggests that several components of PM2.5, once inhaled, can cause inflammation and irritate nerves in the lungs. These responses can start a cascade of changes that adversely affect the rest of the body, Brook said.
"It's possible that certain very small particles, or chemicals that travel with them, may reach the circulation and cause direct harm," Brook said. "The lung nerve-fiber irritation can also disrupt the balance of the nervous system throughout the body. These responses can increase blood clotting and thrombosis, impair vascular function and blood flow, elevate blood pressure, and disrupt proper cardiac electrical activity which may ultimately provoke heart attacks, strokes, or even death.
"These studies also indicate that there is no 'safe' level of PM2.5 exposure," he said.
Recommendations include:
· Physicians should emphasize treatment of traditional cardiovascular risk factors, which may lessen patients' susceptibility to air pollution.
· All patients with cardiovascular disease should be educated about the risks of air pollution.
· Healthcare professionals should consider educating patients without cardiovascular disease but who are at high risk, such as the elderly, individuals with metabolic syndrome or multiple risk factors and those with diabetes.
· Based on air pollution levels, as forecasted by the Air Quality Index available in many media sources, recommendations for methods to reduce exposure and limit activity should be followed depending on the patient's level of risk.
Reducing exposure to air pollution takes effort at the population level by implementing national policies as well as at the individual level, Brook said. "People can limit their exposure as much as possible by decreasing their time outside when particle levels are high and reducing time spent in traffic – a common source of exposure in today's world."
The American Heart Association and the Environmental Protection Agency are co-sponsoring a Congressional briefing on Capitol Hill to educate lawmakers about the link between air pollution and cardiovascular disease. The association plans to monitor opportunities at the state and federal level to decrease the amount of particulate matter air pollution.
SOURCE American Heart Association
Traffic-related air pollution also increases risk of type 2 diabetes in women
Traffic-related air pollution, known to raise the risk for cardiovascular disease, may also increase the risk of developing type 2 diabetes in women. Low-grade inflammation may contribute to the higher incidence of type 2 diabetes in women exposed to air pollution, according to German researchers.
Published ahead of print in the peer-reviewed journal Environmental Health Perspectives (EHP), the study comprised German women living in highly polluted industrial areas and in rural regions with less pollution. The researchers analyzed data from 1,775 women who were 54 or 55 years old when they enrolled in the study in 1985. Between 1990 and 2006, 187 participants were diagnosed with type 2 diabetes, which often starts in middle age. Air pollution data from monitoring stations and emission inventories run by local environmental agencies were used to estimate each woman's average exposure levels.
Exposure to components of traffic pollution, particularly nitrogen dioxide (NO2) and soot in ambient fine particulate matter (PM), was significantly associated with a higher risk of type 2 diabetes. An increase in NO2 or PM corresponding to the difference between exposure at the 75th percentile and exposure at the 25th percentile was associated with a 15-42% higher risk of type 2 diabetes. Living within 100 meters of busy roadways more than doubled the diabetes risk.
Measurements of C3c, a blood protein and marker for subclinical inflammation, predicted the elevated diabetes risk. Only women with the highest C3c levels at enrollment had an increased risk for type 2 diabetes related to traffic pollution during the 16-year follow-up period. Just how C3c might affect diabetes remains unknown. Immune cells in the airways may first react with air pollutants, setting off a widespread chronic inflammatory response, which in turn may make individuals more susceptible to developing diabetes.
Although the study focuses only on women, study leader Wolfgang Rathmann says, "We have no reason to assume sex differences in the association between air pollution and diabetes risk, but we do not have data on this issue."
To the authors' knowledge, this is the first population-based study to reveal a statistically significant association between traffic-related air pollution and type 2 diabetes. Previous epidemiologic research shows that city dwellers have a higher prevalence of diabetes than do rural residents, especially in developing countries undergoing rapid industrialization. Changes in diet and physical activity and resulting increases in obesity are believed to be the primary culprits. These changes, however, do not totally explain the increased diabetes risk. The results of the current study suggest traffic-related air pollutants may be an unidentified environmental factor related to the development of type 2 diabetes.
Other studies have reported that people with diabetes are more vulnerable to pollution-related cardiovascular disease. Air pollutants can cause low-grade inflammation, insulin resistance, and impaired glucose metabolism. Additionally, C3c is a risk factor for diabetes, and C3c levels are higher in individuals living in highly polluted areas. The latest findings further support the role of traffic air pollutants and low-grade inflammation in diabetes risk.
SOURCE Environmental Health Perspectives (Augustus 2010)
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