Belly fat increases the risk of an age-related eye disease in men, but may have the opposite effect in women.
Excess abdominal fat increases the risk of age-related macular degeneration in middle-age men but may have the opposite effect in women, says a study in the American Journal of Epidemiology.
AMD is a leading cause of blindness in older people, and treatment options are limited. A study of 21,287 Australians, who were followed from their 40s to mid-80s, found that each 0.1 increase in the waist/hip ratio was associated with a 13% increased chance of developing early-stage AMD, and a 75% increased chance of the more severe late-stage AMD, but only in men. Abdominal obesity reduced early AMD risk in women by 7% to 11%. There were 2,694 early and 122 late cases of AMD in the study, which followed the incidences of AMD from 2003 to 2007.
Abdominal fat releases estrogen and other chemicals that may contribute to inflammation associated with AMD, researchers said. The inverse association in women could reflect a genetic resilience to disease seen in older people called the survivorship effect plus the protective effects of long-term estrogen exposure, they said.
Caveat: Information about the onset and duration of obesity wasn't considered. AMD was only measured at follow-up, so the progression of the disease wasn't tracked.
• Coffee and diabetes: Drinking seven or more cups of coffee a week reduced the risk of Type 2 diabetes by 63% in middle-aged Chinese coffee drinkers compared with nondrinkers, according to a study in the European Journal of Clinical Investigation.
The incidence of Type 2 diabetes has increased dramatically in the past decade, especially in developing countries that have adopted Western dietary habits. An estimated 92.4 million Chinese are reported to have the disease. This study examined coffee consumption and diabetes risk in 2,332 Taiwanese men and women age 40 and older in 2004.
Diabetes was present in 14% of men and 10.4% of women. Health, diet, physical activity, income and education were among the factors considered. Results showed fasting glucose levels decreased as coffee consumption rose. Drinking one cup a week cut diabetes risk by 33%; one to six cups reduced the risk by 54%.
Coffee may affect diabetes risk because it contains magnesium, which is known to improve glycemic control and insulin resistance, researchers said. Coffee also increases energy expenditure, contributing to weight loss, they said.
Caveat: Coffee consumption and Type 2 diabetes were self-reported, so misclassification is possible.
• Parkinson's and melanoma: Patients with Parkinson's disease generally have a lower incidence of cancer, especially smoking-related cancers. But a recent meta-analysis found they may be at higher risk for melanoma.
The research, published in Neurology, pooled the results of 12 studies conducted from 1965 to 2010 in North America and Europe. The analysis showed that men with Parkinson's disease were twice as likely to develop melanoma as those without Parkinson's. Melanoma risk was 1.5 times as high in women with Parkinson's as it was in women who didn't have the disease.
The association between Parkinson's and melanoma was found to be bidirectional, meaning melanoma was more common in patients before and after a Parkinson's diagnosis.
Researchers said that Parkinson's and melanoma may share environmental and genetic risk factors. Exposure to pesticides has been linked to a higher risk for both conditions, they said. And higher risk for Parkinson's is also associated with red hair, suggesting that a pigmentation gene may link melanoma and Parkinson's disease, they said. Further research is recommended.
Caveat: Most of the studies weren't designed to evaluate Parkinson's disease and melanoma; melanoma was assessed along with other cancers. Some scientists have suggested the association between Parkinson's and melanoma is due to increased medical surveillance of Parkinson's patients.
• Narrow leg arteries: Women who smoke 15 or more cigarettes a day are 10 times as likely as nonsmokers to develop peripheral artery disease (PAD), a narrowing or blockage of leg arteries due to a buildup of plaque, according to a study in Annals of Internal Medicine.
PAD affects an estimated eight million Americans, causing debilitating cramping and fatigue in the hips, thighs and calves. The condition is associated with an increased risk of heart attack or stroke. Researchers examined the association between smoking and PAD in 39,825 U.S. women health professionals age 45 and older.
The women were monitored annually for an average of 12.7 years starting in 1993. Smoking habits were categorized as never smoked, former smoker, smoked fewer than 15 cigarettes a day, and more than 15 cigarettes a day. There were 178 cases of PAD reported.
The analysis found the risk of PAD increased with the number of cigarettes smoked a day. Former smokers had a three-fold increased risk for PAD compared with never-smokers. The findings reinforce smoking-prevention messages, researchers said.
Caveat: The study only included women who reported symptoms of PAD or had been treated for PAD so it may have missed women with narrowed arteries but no symptoms, researchers said.
• Glasses for migraines: Migraines can be triggered by looking at certain stressful patterns, which have been shown to induce hyperactivity in a part of the brain associated with headaches.
New research, published in the journal Cephalalgia, found that Precision Ophthalmic Tints (POTs), special eyeglasses dyed in different hues for the comfort and perception of individual users, helped to normalize brain activity in migraine sufferers. POTs were compared with gray lenses and control-colored lenses in a U.S. study of 11 migraine patients and 11 headache-free controls.
Each subject was placed in an MRI machine, where brain activity was monitored while the subject looked at nonstressful and stressful patterns through POTs and the gray and control lenses. Nonstressful patterns had minimal effect on both groups; stressful patterns resulted in greater brain activation in migraine patients than controls. Migraine patients reported some relief from all three lenses, but viewing the patterns through POTs reduced discomfort by 70%.
Scans showed the POTs suppressed activity in several key areas of the brain. Researchers said these areas may be useful biomarkers in developing new treatments for migraine.
Caveat: The U.K. Medical Research Council owns the rights to the POTs and the Intuitive Colorimeter, the technology used to tint the POTs. One of the study's five researchers receives a portion of royalties on sales of the Colorimeter as a Council award to inventors.
• Cancer protection: Prospective mothers who supplement their diet with folic acid and other B vitamins before conceiving may be protecting their offspring against colorectal cancer in adulthood, research published in the journal Gut suggests. Maternal nutrition is increasingly recognized as a determinant of chronic disease in offspring. Studies have shown that high maternal folic acid (folate) intake protects against certain pediatric cancers.
In this U.S. study, female mice genetically predisposed to develop colon cancer were fed varying amounts of folate and vitamins B-2, B-6 and B-12 for four weeks before mating. One group received a mildly vitamin-deficient diet, a control group got a vitamin-replete diet and a third group received supplements.
The diets continued throughout pregnancy until weaning. At that point, all offspring were put on a vitamin-replete diet. At eight months, intestinal tumors were detected in 56% of offspring from mothers on the vitamin-deficient diet, and in 59% of offspring from the control group. Among offspring of mothers who received supplements, 21% had intestinal tumors. The strongest tumor-suppressing genes were found in offspring from supplemented mothers, a finding that could have potential public health significance, researchers said.
Caveat: It's not known if maternal consumption of folate and the three B vitamins before conception could prevent colon tumors from developing in humans.
• Androgen deficiency: Abnormally dilated testicular veins called varicocele, which affect 15% of men after puberty, were associated with significantly lower testosterone levels, or androgen deficiency. The research, published in BJU International, also found that surgical correction of varicocele significantly increased testosterone levels in 70% of patients.
Varicocele is present in one-third of men seeking treatment for infertility. Studies have shown larger varicocele causes more severe damage to testicular function.
In this study, testosterone was measured in 325 U.S. men with varicocele and 510 men without varicocele who had undergone a vasectomy reversal.
The average age of the varicocele and control groups was 35 and 43 respectively. Microsurgery boosted testosterone levels by up to 50% in 58 men, by 51% to 100% in 27 men and by more than 100% in 14 men. Testosterone was unchanged in 43 men.
Varicocele is a risk factor for premature androgen deficiency, and surgery to repair varicocele may reduce that risk, researchers said.
Caveat: Most subjects with varicocele had been evaluated for infertility so the population wasn't entirely homogeneous, researchers said. A random group of men without fertility issues might have made a better control group than men seeking vasectomy reversal, they said.
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