Overweight and obese people shouldn't put off regular physical exercise because of worries it could lead to osteoarthritis of the knees, according to a report in the Journal of Epidemiology & Community Health. A study of overweight and obese people found their risk of knee osteoarthritis was significantly higher than normal-weight individuals but exercise didn't increase that risk.

Previous studies examining the effects of recreational exercise on osteoarthritis risk have had mixed findings.

Researchers analyzed osteoarthritis risk in nearly 30,000 Norwegian women and men enrolled in national health surveys from 1984 to 1997. Subjects were in their mid-40s and pain-free at the start. Just over a third of the participants exercised an hour or more per week and were considered physically active. Physician-diagnosed osteoarthritis was reported by the subjects.

Risk of knee osteoarthritis was more than four times as high in obese men and women as normal-weight subjects over 11 years of follow-up, the study found. But there was no additional risk associated with exercise or exercise intensity for any body-mass-index category, the analysis showed. Hip osteoarthritis wasn't linked to either high BMI or exercise.

Caveat: Information about types of exercise performed wasn't available. It is possible participation in high-impact sports can increase the risk of knee and hip osteoarthritis within all categories of BMI, researchers said.

Ann Lukits

• physical [´fizikəl]   a.物质的；有形的   (初中英语单词)
• journal [´dʒə:nəl]   n.日记；日报；杂志   (初中英语单词)
• additional [ə´diʃənəl]   a.附加的，额外的   (初中英语单词)
• analysis [ə´næləsis]   n.分解；分析(结果)   (初中英语单词)
• available [ə´veiləbəl]   a.可用的；有效的   (初中英语单词)
• community [kə´mju:niti]   n.团体；社区；公众   (高中英语单词)
• intensity [in´tensiti]   a.激烈；强度；深度   (高中英语单词)
• norwegian [nɔ:´wi:dʒən]   a.&n.挪威人(语)(的)   (英语四级单词)
• physically [´fizikəli]   ad.按照自然规律   (英语四级单词)
• category [´kætigəri]   n.种类；部属；范畴   (英语六级单词)
• participation [pɑ:,tisi´peiʃən]   n.参加，参与   (英语六级单词)