Monday, October 04, 2010

Women Who Get Dental Care Have Lower Risk of Heart Disease, Says Study

The usual rubbish. Richer women are more likely to be able to afford dental care and rich people are healthier anyway

A new study led by a University of California, Berkeley, researcher could give women a little extra motivation to visit their dentist more regularly. The study suggests that women who get dental care reduce their risk of heart attacks, stroke and other cardiovascular problems by at least one-third.

The analysis, which used data from nearly 7,000 people ages 44-88 enrolled in the Health and Retirement Study, did not find a similar benefit for men.

Published online Sept. 29 in the journal Health Economics, the study compared people who went to the dentist during the previous two years with those who did not.

"Many studies have found associations between dental care and cardiovascular disease, but our study is the first to show that general dental care leads to fewer heart attacks, strokes, and other adverse cardiovascular outcomes in a causal way," said study lead author Timothy Brown, assistant adjunct professor of health policy and management at UC Berkeley's School of Public Health.

In the world of health and medical studies, causality is typically determined through randomized controlled trials in which two or more groups of people are essentially equal, except for the receipt of a treatment or intervention, such as a new drug, a periodontal procedure or a health education class. The group that did not receive the treatment -- the control group -- is compared with the group that did. Differences in outcomes between the groups are attributed to the treatment.

But randomized controlled trials are not always possible, so researchers sometimes turn to a statistical approach called the method of instrumental variables to rule out other potential factors that could account for different outcomes between groups. The use of instrumental variables is common among economists to evaluate the effects of economic policies, but it is less well-known in the clinical setting.

"While relatively short randomized controlled trials of specific types of dental treatment are possible, we can't run long-term randomized controlled trials of whether general dental care reduces cardiovascular disease events like heart attacks and strokes," said Brown, a health economist. "Individuals randomized to the treatment group would enjoy general dental care and those randomized to the control group would get no dental care at all. Many, if not most, people in the control group would simply get dental care on their own, destroying the experimental design, and making the results of the experiment worthless. The method of instrumental variables allows us to avoid this problem."

The method helped researchers rule out self-selection bias, or the possibility that people who seek out dental care are different -- perhaps healthier in general -- than those who don't.

Data from the Health and Retirement Study had been collected every two years from 1996 to 2004. This longitudinal study followed the same individuals over time, and each biennial survey included questions on whether subjects had visited the dentist and whether they had experienced a heart attack, stroke, angina or congestive heart failure during the prior two years. Deaths from heart attacks or strokes were also included in the analysis. The study took into account other risk factors, such as alcohol and tobacco use, high blood pressure and body mass index.

The fact that men and women did not benefit equally from dental care did not completely surprise the researchers. "To my knowledge, previous studies in this area have found that the relationship between poor oral health and cardiovascular disease markers varies by gender, but none have examined differences between men and women with regard to actual cardiovascular disease events," said Brown, who is also associate director of research at UC Berkeley's Nicholas C. Petris Center on Health Care Markets & Consumer Welfare.

"We think the findings reflect differences in how men and women develop cardiovascular disease," said study co-author Dr. Stephen Brown, a first-year obstetrician/gynecologist resident at the West Virginia University Charleston Division School of Medicine. "Other studies suggest that estrogen has a protective effect against heart disease because it helps prevent the development of atherosclerosis. It's not until women hit menopause around age 50 to 55 that they start catching up with men."

The study authors suggest that for dental care to have a protective effect, it should occur early in the development of cardiovascular disease.

The researchers did not have data on the type of procedures used during the dental visit, but they pointed to other studies that indicated three-fourths of older adult dental visits involved preventive services, such as cleaning, fluoride and sealant treatments.


Death rates INCREASED by 20mph zone... and getting rid of cameras reduces accidents

Reducing the speed limit to 20mph in all residential streets does not significantly improve road safety, an official report has revealed.

Towns around the country [Britain] are planning to introduce the limit in the belief that lower speeds save lives. However, analysis of the first citywide scheme in Portsmouth has shown the number of people killed or seriously injured actually increased after the speed limit was reduced from 30mph.

While the 20mph limit has been widely implemented in specific streets, for example near primary schools, the case for reducing the limit in all residential streets appears to have been badly damaged by the Department for Transport report.

Analysis by consultants Atkins, on behalf of the Department for Transport, found the average number of people killed or seriously injured annually in Portsmouth rose from 18.7 to 19.9 after the scheme was launched in 2007.

Motorists' average speeds reduced by only 1.3mph to 18.5mph. The Portsmouth speed limit is not enforced by speed humps or cameras, instead relying on motorists obeying the law.

Previous studies have found that 20mph zones in which traffic-calming measures are also deployed produce bigger reductions in drivers' average speeds.

City centre 20mph zones have been introduced in Newcastle upon Tyne, Oxford, Edinburgh and Bristol.

Norman Baker, the Liberal Democrat transport minister, has given his backing to 20mph limits. Earlier this year he said: 'For a child being hit at 30mph and 20mph is the difference between life and death. 'But this is also about making our town centres more attractive places to live and work, and reducing carbon emissions by encouraging people to cycle or walk.'

A spokesman for the transport department said: 'This report by an independent contractor on the Portsmouth scheme is one of several research documents available to help councils decide whether they want to put in place 20mph zones or limits. 'It is up to local authorities to make these decisions using their knowledge of local roads and in consultation with local communities.'

Meanwhile a town where all the speed cameras were switched off has reported a sharp drop in the number of accidents. Over the past year there have been 14 minor and two serious accidents in the streets of Swindon monitored by cameras. This compared with 15 minor, five serious and one fatal accident in the same streets the previous year when cameras were operational.

Roderick Bluh, leader of the Tory-controlled council, said: 'it is beginning to look as though we were right all along when we said these cameras were revenue raisers.'


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