Wednesday, January 26, 2011

Traffic noise boosts risk of stroke - study

Findings of this nature are common and it usually transpires that controls for income and wealth have not been applied. Since poor people have worse health and tend to live in less salubrious locations, the findings can be seen as nothing more than another demonstration that poorer people have worse health. People tend to live by busy roads only if they can afford nothing better. The abstract below mentions no controls for income so would appear to fall into that category

As old people tend to be poorer in income terms, the fact that the association was found only among the elderly may reinforce the suspicion that we are looking at an income or wealth effect only.

A complication is that income and wealth are not strongly associated among the elderly and both could affect how well the person could afford to live.

Exposure to road traffic noise boosts the risk of stroke for those 65 or older, according to research published online today in the European Heart Journal.

In a survey of more than 50,000 people, every 10 additional decibels of road noise led to an increase of 14 per cent in the probability of a stroke when averaged for all age groups. For those under 65, the risk was not statistically significant. But the risk was weighted hugely in the over-65 group, where it rose 27 per cent for each 10 decibel increment. Above 60 decibels or so, the danger of stroke increased even more, the researchers found.

A busy street can easily generate noise levels of 70 or 80 decibels. By comparison, a lawnmower or a chainsaw gives off 90 or 100 decibels, while a nearby jet plane taking off typically measures 120 decibels.

"Previous studies have linked traffic noise with raised blood pressure and heart attacks," said lead researcher Mette Sorensena of the Danish Cancer Society. "Our study shows that exposure to road traffic noise seems to increase the risk of stroke."

The study reviewed the medical and residency histories of 51,485 people who had participated in the Danish Diet, Cancer and Health survey, conducted in and around Copenhagen between 1993 and 1997. A total of 1881 people suffered a stroke during this period.

Eight per cent of all stroke cases, and 19 per cent of cases in those aged over 65, could be attributed to road traffic noise, according to the paper.

The researchers suggest noise acts as a stressor and disturbs sleep, which results in increased blood pressure and heart rate, as well as increased level of stress hormones. The study factored in the effect of air pollution, exposure to railway and aircraft noise, and a range of potentially confounding lifestyle factors such as smoking, diet and alcohol consumption.

The survey cohort lived mainly in urban areas and was thus not representative of the whole population in terms of exposure to road traffic noise. Proximity to road noise is also related to social class, as wealthier people can afford to live in quieter areas.


Road traffic noise and stroke: a prospective cohort study

Mette Sørensen et al.


Aims: Epidemiological studies suggest that long-term exposure to road traffic noise increases the risk of cardiovascular disorders. The aim of this study was to investigate the relation between exposure to road traffic noise and risk for stroke, which has not been studied before.

Methods and results: In a population-based cohort of 57 053 people, we identified 1881 cases of first-ever stroke in a national hospital register between 1993–1997 and 2006. Exposure to road traffic noise and air pollution during the same period was estimated for all cohort members from residential address history. Associations between exposure to road traffic noise and stroke incidence were analysed in a Cox regression model with stratification for gender and calendar-year and adjustment for air pollution and other potential confounders. We found an incidence rate ratio (IRR) of 1.14 for stroke [95% confidence interval (CI): 1.03–1.25] per 10 dB higher level of road traffic noise (Lden). There was a statistically significant interaction with age (P < 0.001), with a strong association between road traffic noise and stroke among cases over 64.5 years (IRR: 1.27; 95% CI: 1.13–1.43) and no association for those under 64.5 years (IRR: 1.02; 95% CI: 0.91–1.14).

Conclusion: Exposure to residential road traffic noise was associated with a higher risk for stroke among people older than 64.5 years of age.


Fatty Footprints: A Modest Proposal Based on Liberal GroupThink

Fact: The USA is in the midst of a obesity epidemic.

Fact: Fat people are more likely to need health services, work fewer years, and pay less in taxes. They “free ride” by consuming scarce health care resources paid for by those who are healthy and thin.


For their own good, and for the Public Good, the Departments of Health (state and federal) will calculate the “fat footprint” of every product that enters the stream of interstate commerce (by definition, everything in the universe). A new value added tax (VAT) will be added to all food items to cover health care costs and encourage healthy behavior on the part of those “irresponsible” fat people.

The government will also require all state and federal workers to work out at their local gym, eat food from an approved list, and reduce their weight to a level deemed adequate by F.A.T.S. (Federal Agency for Trimming and Slimming America).

This regulation will also extend to employees of businesses that contract with the federal government. Currently. F.A.T.S. is working to devise universal coverage beyond those groups. After all, one reason why children are “left behind” is that they are too fat to catch up with their peers. This must change.

Civil rights laws will be revised to add thin-to-normal weight people to the list of protected classes for affirmative action purposes. Employers must seek out thin-to-normal weight employees by casting a wide net in their recruitment. These workers will boost the bottom line of companies and make for a more socially just distribution of resources. The EEOC will supervise the formulation of goals and timetables to achieve real progress.

The tax code will extend credits to those who can document weight loss. Other candidates for tax subsidies: those with reduced cholesterol levels, lower blood pressure, and other markers of good health.

A half century ago, normal-weight president John F. Kennedy said, “Ask not what your country can do for you, ask what you can do for your country.” His promise lays unfulfilled next to the potato chips on millions of American couches.

Fifty years is too long, we know what you can, should, and must do for your count


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