Study sees main road link to asthma risk
TRAFFIC fumes may be just annoying to most of us, but in children already at increased risk of asthma such pollution could be enough to bring on the disease. In a new study in the medical journal Thorax , scientists collected mouth-swab DNA samples from 3124 children aged 10 to 16. They looked for variations in genes that help clear the body of the harmful air pollutants known as polyaromatic hydrocarbons (PAH). Children whose genes resulted in active clearance of PAH were up to four times more likely to suffer from asthma as those with very low clearance activity. From maps, the distance between each child’s house and the nearest major road was calculated. Among children with active PAH clearance, those who lived less than 75m from a main road were up to nine times more likely to have asthma as those who lived further away. Thorax 2007;doi:10.1136/thx.2007.080127 (Salam MT, et al) WOMENwith dementia start losing weight at least 10 years before the disease is diagnosed, says a study published in the current issue of Neurology , making weight an important factor to monitor in older adults. Researchers examined the records of 481 people with dementia and 481 people of the same age and gender who did not have dementia. Between 21 and 30 years before dementia was diagnosed, the average body weight was the same in both groups. But the women who would later develop dementia started losing weight up to 20 years before the disease was diagnosed. On average, those with dementia weighed 5.4kg less than those without the disease in the year of diagnosis. The authors suggest that weight loss may be due to the apathy, loss of initiative and decreased sense of smell that can occur in the very early stages of dementia. Neurology 2007;69:739-746 (Knopman DS, et al) DIETS high in the nutrient choline may increase the risk of colorectal polyps — outgrowths of tissue that can sometimes lead to colorectal cancer — according to a new study in the JournaloftheNationalCancer Institute . Major food sources of choline include red meat, eggs, poultry, and dairy products. Researchers sent diet surveys to 39,246 women enrolled in the Nurses’ Health Study every two to four years from 1984 to 2002. They then estimated the choline content in their diets. During the study period there were 2408 cases of polyps. Greater amounts of choline in the diet were associated with an increased risk of colorectal polyps. Compared to those consuming the lowest levels of choline, those in the top 20 per cent for choline consumption were 45 per cent more likely to have colorectal polyps. J Natl Cancer Inst 2007;99:1224-1231 (Cho E, et al) SOME organ transplant patients could live free from anti-rejection drugs, with scientists finding a way to identify those most likely to stay healthy without medication. Researchers took blood samples from 16 healthy volunteers and three groups of kidney transplant patients — 22 patients on anti- rejection drugs that were working successfully, 36 patients on anti-rejection drugs that were not working, and 17 ‘‘ tolerant’’ people who had stopped taking their medication with no sign of organ rejection. Using gene chip (microarray) technology, researchers compared the genes present in the blood samples and found that the expression pattern of 33 genes was shared by 90 per cent of the tolerant patients. The findings, published in the Proceedingsofthe NationalAcademyofSciences , suggest that patients regularly taking anti-rejection drugs who have the same pattern of tolerance genes may be able to safely reduce or even stop taking their medication. And just as importantly, those who don’t share the gene pattern should be encouraged to continue taking the drugs. Proc Natl Acad Sci USA 2007; 104 (Sarwal M, et al) BROCCOLI and its relatives could have the power to boost the immune system and even fight cancer, according to new research in the JournalofNutritionalBiochemistry . One of the active ingredients in broccoli, cabbage and kale (another type of cabbage) is 3,3’-diindolylmethane or DIM. Researchers fed DIM to mice at a high concentration of 30mg per kilogram of body weight and found that it increased blood levels of a number of cytokines — proteins that drive the immune system — including interleukin-6, granulocyte colony-stimulating factor, interleukin-12 and interferon-gamma. Mice were also infected with reoviruses, which live in the intestines but are not life-threatening. Mice that were given an oral dose of DIM were much better at clearing the virus from their gut compared to those that had not been fed DIM. The authors suggest that these effects on the immune system could also protect against cancer. J Nutr Biochem 2007;doi:10.1016/j.jnutbio.2007.05.004 (Xue L, et al) ALCOHOL consumption could lead to faster disease progression in patients with HIV (human immunodeficiency virus), concludes a new study in the Journal of Acquired Immune Deficiency Syndromes . Alcohol use is common among HIV-infected persons, say the authors. They assessed alcohol consumption, virus levels and CD4 T cell numbers (a measure of virus activity) in 595 HIV-infected patients with alcohol problems. Among those who were not taking anti-retroviral therapy (ART), heavy drinking was associated with a lower CD4 T cell count, indicating more severe disease. The same did not hold true for those taking anti-retroviral drugs. According to the authors, the findings suggest that HIVinfected persons who drink heavily and are not on ART might decrease their risk of disease progression if they abstain from alcohol use. JAIDS 2007;doi:10.1097/QAI.0b013e31814 2aabb (Samet JH, et al) Want to know more? Items are referenced where possible. A reference such as ‘‘ 2007;35:18-25’’ means the source article was published on pages 18-25 in volume number 35 of the publication, in 2007. A doi number or website address is used for research published on a journal’s website.
Traffic: Living near highway pollution is bad for asthmatics