October 18, 1994
Media Contact:Marc Kusinitz
Phone: (410) 955-8665
Men carrying a few extra pounds in early adulthood nearly double their chance of developing painful knee and hip osteoarthritis later in life, say Johns Hopkins researchers. A new study reports that even small bulges can cause big problems.
"All it takes is an extra 20 pounds," says Allan C. Gelber, M.D., M.P.H., who is scheduled to present the new findings October 25 at The American College of Rheumatology's 58th Annual Scientific Meeting in Minneapolis.
"Those extra pounds may cause undue stress and cartilage breakdown in weight- bearing joints over time," says Gelber.
The good news is that body weight is a modifiable trait, he says.
The bad news: a recent national study reports that one-third of U.S. adults aged 20 or older, regardless of race or gender, are overweight.
The findings emerge from a long-term study in which researchers followed 1,178 men through 1994 who entered The Johns Hopkins School of Medicine from 1948 through 1964. Their average age was 22 years when they entered medical school--a significant fact, says Gelber, since no other study has evaluated men from such an early age, throughout their adulthood. In addition, people are most susceptible to major weight gain from ages 25 to 35.
Over the years, investigators recorded participants' height, weight and age, in addition to hip and knee osteoarthritis. Overall, the average height of study participants was 5' ll" and average weight, 168 pounds.
The heaviest students averaged 190 pounds and were three and a half times more likely to develop osteoarthritis in their weight-bearing joints than the lightest students (average weight, 146 pounds.) "Researchers have been faced with the chicken and egg dilemma," explains Gelber. "It was unclear from previous studies if being overweight led to osteoarthritis because the joint had to work harder, or if osteoarthritis led to a sedentary lifestyle and subsequent weight gain. These results shed new light on that question."
Osteoarthritis is the most common form of arthritis and a major cause of disability and missed workdays. More than 40 million Americans have been diagnosed with osteoarthritis. Some use medications or have joint replacements to temper their pain.
According to Gelber, osteoarthritis is a mechanical problem. Aging and use together with genetic and biologic factors wear the cartilage thin, or destroy it altogether. Without an adequate thick shock absorber, bone meets bone, causing friction and pain. (Other kinds of arthritis, such as rheumatoid arthritis, are caused by inflammation and affect more than one percent of adults in the United States.)
Other researchers on the study include Lucy A. Mead, Sc.M., Fredrick M. Wigley, M.D., Marc C. Hochberg, M.D., M.P.H., David M. Levine, M.D., M.P.H., Sc.D., and Michael J. Klag, M.D., M.P.H.
The Johns Hopkins study is funded by the National Institutes of Health. Designed by Caroline Bedell Thomas, M.D., it is one of the nation's longest-running studies and is aimed at finding early predictors of disease and mortality. Begun in 1947, it continues to follow more than 1,000 men and women who have enrolled in The Johns Hopkins University School of Medicine and has yielded more than 130 research papers.
Dr. Gelber received a post-doctoral fellowship award from the National Arthritis Foundation to perform this study.
Source: Robert J. Kuczmarski, Dr.Ph., Rd et al, Increasing Prevalence of Overweight Among US Adults: The National Health and Nutrition Examination Surveys, 1960-1991, Journal of the American Medical Association, 1994,272:205-211.