Introduction: As the community ages, conditions affecting the quality of life and activity of older people become of increasing concern. Urinary incontinence (UI) is defined as any involuntary leakage of urine. More than a half of the middle-aged and elderly women have experienced UI in Japan. Although UI is not life threatening, it is a disease that causes personal distress and social handicaps and worsens quality of life. Some special pelvic floor muscle training has been recommended to protect against UI or to reduce its volume. However, it is somewhat troublesome to maintain special training for a long term. It might be easier to keep daily physical activity or physical fitness but little is known about whether they have an effect on the prevention of UI.
Purpose: The purpose of the current study was to evaluate the effect of daily physical activity and physical fitness on the incidence of UI among community-dwelling middle-aged and elderly women.
Methods: The data for the current study were derived from the second- and fourth-wave examination of the National Institute for Longevity Sciences-Longitudinal Study of Aging (NILS-LSA). Among 847 women aged 41-82 years who participated in both examinations, 414 (48.9%) had not experienced UI at the second-wave examination (baseline). After 4.2 years follow-up, at the fourth-wave examination, 79 (19.1%) suffered from newly onset UI. Leisure-time and on-the-job physical activity were assessed using a questionnaire at the baseline and follow-up examinations. Gait velocities, step frequencies, and step lengths at comfortable and maximum gait were estimated in 10-m walking. As for physical fitness, muscle strength and power, such as grip strength, sit-up, knee-extension strength, and leg-extension power. were also measured at both examinations. The effects of physical activity or physical fitness on the prevention of UI were assessed by multivariate logistic-regression analyses controlled for age, body mass index, and parity, using SAS 9.1.3. Statistical significant probability levels were set to .05.
Results: The women who did 2.5 METs or more leisure-time physical activity at both examinations showed lower risk of onset of UI compared with those who did not at both examinations (Odds ratio: 0.473, 95% confident interval: 0.251-0.892). Those who did 4.5 METs or more on-the-job physical activity at baseline, who walked with higher frequency in fast walking at baseline, who walked with higher frequency in comfortable walk at the follow-up examination, and who walked with higher frequency and higher velocity in fast walking at the follow-up examination also showed lower risk of onset of UI. On the other hand, none of muscle strength and powers at baseline and follow-up examinations showed significant relationship with the risk of incidence of UI.
Conclusion: Physical activities, especially moderate leisure-time physical activity and walking with high frequency, may prevent onset of UI in middle-aged and elderly women.