Knees Buckling Under Pressure

Knee osteoarthritis risk affected by BMI and occupation

(RxWiki News) Your body weight and your job may be putting considerable pressure on your knees. This pressure could lead to a medical condition called knee osteoarthritis.

A recent study found that having a higher body mass index (a measure of height and weight) and living a more active lifestyle were both associated with a higher risk of knee osteoarthritis.

The study also found that for people with more active lifestyles, the chance of having knee osteoarthritis was reduced if they had a lower BMI.

"Speak to your doctor about healthy weight management."

This study was led by Kathryn Martin, PhD, from the Laboratory of Epidemiology and Population Sciences in the National Institute on Aging.

The research team examined the impact that job and leisure-related activities had on the risk of developing knee osteoarthritis. In addition, they looked to see whether these activities changed the association between body mass index (BMI) and risk of knee osteoarthritis — a condition that occurs when the knee joints are put under significant stress and eventually become damaged.

For this study, Dr. Martin and team used data from the 1946 British birth cohort study, specifically focusing on 2,597 individuals who had a clinical exam and diagnosis of knee osteoarthritis at age 53.

BMI, job-related physical activities and leisure-related physical activities were determined when participants were three different ages (35 or 36, 43, and 53).

For leisure-related physical activities, participants reported whether they had participated in any sports, vigorous leisure activities or exercises, and if so, how often in the past year. The researchers then split participants into three categories based on their answers: inactive, less active and most active.

For job-related physical activities, the researchers asked participants about their jobs and then categorized them as having a manual or non-manual labor job. Based on the participants' jobs, the researchers then determined the type of physical activities that each job would likely involve, such as heavy lifting, kneeling or squatting.

Many factors were taken into account when analyzing the data, including gender, diagnosis of other health conditions, family history of arthritis, history of knee injury, education and social class.

The researchers found that a higher BMI was significantly associated with knee osteoarthritis for both men and women.

It was also found that those who had manual labor jobs had a greater chance of developing knee osteoarthritis. The researchers did find, however, that for those with more active lifestyles, the chance of developing knee osteoarthritis was reduced if they had a lower BMI when compared to those with a higher BMI.

These findings suggest that a lower BMI may reduce the risk of knee osteoarthritis brought on by a more active lifestyle.

This study was published on July 24 in BMC Musculoskeletal Disorders.

The authors declared no competing interests.

Review Date: 
July 25, 2013