Lengthier smoking habits—but not more intense ones—seem to reduce the odds of developing Parkinson’s disease, according to a study in Neurology. The inverse association between smoking and Parkinson’s—the neurodegenerative disease characterized by difficulty in controlling movement and speech—was first reported half a century ago, but this is the first study to separate the number of years smoking from the number of cigarettes smoked per day. Researchers compared the smoking histories of 305,468 elderly subjects, 1,662 of whom had been diagnosed with the disease in the previous decade. Compared to the nonsmokers, subjects who had smoked at least a pack a day for one to nine years were only 4% less likely to develop Parkinson’s. But subjects who smoked as many cigarettes a day for more than 30 years had 41% shorter odds of developing the disease. The number of cigarettes a day, however, had no significant independent effect on Parkinson’s risk. The results suggest that any Parkinson’s-protective effects of tobacco reach saturation at low doses, the researchers said.
Caveat: It is possible that genetic factors determine both the propensity to smoke and protection from Parkinson’s, rather than the smoke protecting against Parkinson’s. Smokers may have remembered the duration of their habit more accurately than its intensity, which would skew the findings.
Read the Study: Smoking duration, intensity, and risk of Parkinson’s disease
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Stroke: Month-to-month fluctuations in blood pressure indicate a higher risk for stroke, according to an analysis in the Lancet. The researchers re-examined data from four large studies of patients who had already had a stroke or transient ischemic attack, sometimes called a mini-stroke. Average systolic blood pressure—the peak pressure, measured when the heart is contracting—is known to increase the risk for strokes. But this study also found that the more patients’ systolic blood pressure varied at three- or four-month intervals, the more likely they were to have another stroke. In the central experiment, for instance, the 10% of patients with the greatest blood-pressure variation were more than three times as likely to have another stroke as the 10% of patients with the smallest fluctuations. Stabilizing such fluctuations could be an important target for anti-stroke drugs, the researchers suggested.
Caveat: The association between blood pressure fluctuations and stroke might not apply to people without a history of stroke or transient ischemic attacks. Average systolic blood pressure is still a useful measure, the researchers cautioned.
Read the Study: Prognostic significance of visit-to-visit variability, maximum systolic blood pressure, and episodic hypertension
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Fat: Having more-sensitive fat receptors in your mouth may help control your weight, according to a study of 54 subjects in the British Journal of Nutrition. The subjects kept detailed diaries of what they ate during a two-day stretch. Researchers then tested how well those subjects could distinguish between custards with varying fat contents. The 12 subjects with the keenest sense for fat had consumed on average 17% fewer calories and 29% fewer grams of fat than the other participants, according to the food diaries, and had slightly lower body-mass indices.
Caveat: It’s possible that habitually high fat consumption—as has been observed with sodium consumption—desensitized some participants to fat over time, rather than fat-insensitivity leading them to eat more. Larger, lengthier studies are needed to confirm the findings.
Read the Study: Oral sensitivity to fatty acids, food consumption and BMI in human subjects
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Pain: A genetic mutation makes some people experience more pain than others, according to a study in the Proceedings of the National Academy of Sciences. Variations in the gene SCN9A have previously been linked to several pain disorders, but not to pain in the general population. Researchers in this study found that among 578 people with osteoarthritis, those with one particular mutation reported feeling more pain. That variation, present in about 10% of SCN9A copies, was also associated with increased pain among subjects with sciatica and amputees with “phantom pain.” Future drugs could target SCN9A to more effectively relieve pain, the researchers said.
Caveat: Pain was chiefly determined by the subjects’ own reckoning, rather than by any biological measure. There were no statistically significant links between the gene mutation and pain in patients with pancreatitis or people recovering from lumbar-disk surgery.
Read the Study: Pain perception is altered by a nucleotide polymorphism in SCN9A
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Industry Influence: Authors who dismissed the safety risks of a controversial antidiabetes drug were much likelier than more skeptical authors to have financial ties to the drug’s manufacturer, according to a study in BMJ. In 2007, a large meta-analysis of rosiglitazone (marketed as Avandia and as a component of Avandaryl and Avandamet by GlaxoSmithKline) found that the drug increased the risk of heart attack for diabetic patients, sparking a debate staged in letters, commentaries and additional reviews. For the present study, Mayo Clinic researchers identified 202 such articles, written by 180 different authors, and classified their stances on the safety of rosiglitazone into three groups: favorable, neutral and unfavorable. Among the 31 authors of favorable articles, 87% of them had financial conflicts of interest with GlaxoSmithKline. By contrast, 24% of the 84 authors of neutral articles and 20% of the 65 unfavorable authors had financial ties to the company.
Caveat: The researchers were unable to compare the authors’ stance on rosiglitazone with the magnitude of the financial ties. The findings don’t prove that pro-rosiglitazone authors were financially motivated, the researchers cautioned.
Read the Study: Association between industry affiliation and position on cardiovascular risk with rosiglitazone: cross sectional systematic review
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Healing After Sealing: Hip-surgery wounds are four times as likely to develop an infection when closed with metal staples instead of nylon stitches, according to a review in BMJ. The researchers analyzed six studies that compared staples to sutures in orthopedic surgery, comprising 683 wounds. Despite the disparity in infections, they found no increased risk of inflammation, wound reopening or other negative outcomes. Studies of other operations, such as abdominal surgery, have found no difference between stitches and staples in the risk for infection. Both stitches and staples are commonly used in the U.S. for closing wounds.
Caveat: There weren’t enough data to determine the effect of stitches versus staples on knee operations. Only three of the six studies randomized their subjects.
Read the Study: Sutures versus staples for skin closure in orthopaedic surgery: meta-analysis