Osteoarthritis and Hip Replacement Risk LOWERED by Running and Walking

Introduction

Osteoarthritis (OA) is the leading cause of disability as we get older. It affects between 7% and 25% of caucasians over 55 years of age and more common in women than men. There has long been this myth that running and other strenuous sports increase OA risk, more so than walking and less-strenuous activities. This myth is based on the fact that running causes knee injuries and damage that are both well known risk factors for OA of the knee. However, the lower body mass index (BMI) as a measure of weight for height, is known to lower the risk of knee OA. Analyses were therefore performed to test whether running, walking, and other exercise affect OA and hip replacement risk and to assess the role of body mass index (BMI) in mediating these relationships.

The Research

Data from 74,752 runners from the USA-based National Runner’s Health Study and 14,625 walkers from the National Walkers Health Study were tracked over 5.7 years in this study.  The runners and walkers were asked many questions including whether they had physician-diagnosed OA and hip replacement during that time, their height and weight to determine BMI (kg/squared meter of height), and how much exercise they did in terms of energy expenditure per day (light, moderate or vigorous).

The Results

Older age was associated with increased risk of OA, increasing by 3.9% per year in men and 6.1% in women. Risk of hip replacement increased by 7.4% in men and 10.6% per year in women. In the runners, 2004 (2.7%) reported OA and 259 (0.4%) reported hip replacements whereas 696 (4.8%) walkers reported OA and 114 (0.8%) reported hip replacements during the 5.7 years of follow-up. Compared with non-running activity in the runners, the risks for OA and hip replacement decreased as follows: 1) 18.1% and 35.1% with light intensity running; 2) 16.1% and 50.4% for the moderate intensity running; and 3) 15.6% and 38.5% for vigorous running. Baseline BMI was strongly associated with both OA (5.0% increase per kilogram per square meter) and hip replacement risks (9.8% increase per kilogram per square meter). The reductions in OA and hip replacement risk by increasing the intensity of running did not differ significantly between runners and walkers.

So What?

Running significantly reduced OA and hip replacement risk due to, in part, running’s association with lower BMI. It appears the known benefits of exercise promoting cartilage thickening and preventing loss of the viscosity and elasticity of the cartilage help prevent OA. So stay slim into older age and keep runnin!

For older athletes wanting to stay both illness- and injury-free, please read Chapters 12 (Injury prevention and management for the masters athlete) and 14 (Staying healthy and illness-free) in my book The Masters Athlete now available in pdf format online.

Source: Williams, P. (2013). Effects of running and walking on osteoarthritis and hip replacement risk. Medicine and Science in Sports and Exercise, 45(7): 1292-1297.