[Health behavior for prevention of knee pain among young-old persons living in a rural area: focus on presence of knee pain and sex differences].

To determine the prevalence of knee pain, and implementation status of health behavior for knee pain among young-old persons living in a rural area in Japan by sex, and to study related factors. An anonymous self-administered questionnaire covering demographic variables, lifestyle such as smoking, drinking, farm work, snow removal, 'ochanomi' (tea break with friends), hospital visits, knee pain, JKOM (Japanese knee osteoarthritis measure) and health behavior was distributed to 2,758 persons aged 65 to 74 years living in Minamiaizu town, a rural and snowy town of Fukushima Prefecture in November, 2008. Valid responses were obtained from 1,415 (response rate: 51.3%). The prevalence of knee pain was 35.1%, and twice as many women as men had pain in their knees. People with knee pain had a higher body mass index, higher risk of motor deterioration, lower frequency of going out, and more hospital visits than people without knee pain. Health behavior was emphasized by 657 persons (46.3%), and the rate was higher in people with knee pain. As to companions and information source for health behaviors, 'ochanomi' friends were popular for women and family members for men. Walking was more common and exercise and diet were less common in men than in women. Among the women with knee pain, the implementation rate of health behavior was higher in non-smokers, farm workers, and 'ochanomi' participants than in others. Among men without knee pain, the implementation rate was higher in non-smokers and in people with high scores on the JKOM subscale of "pain or stiffness" and "health status". Among women without knee pain, more people living alone and going out once or more a week focused on health behavior more than the other people. The prevalence of knee pain in this study was similar to that in a previous study on elderly living in a mountain area. Type, information source, companion and related factors of health behavior differed by sex and presence of knee pain; therefore, approaches for encouraging health behavior should be suited to the target population's characteristics. Many people obtain information from non-professionals, so health care workers should provide details about adequate methods for health behavior in a careful manner.