Unhealthy foodsMany people mistake arthritis for an old-person’s ailment, but that’s not the case. The misconception that young people are immune is one patients with “a kind of vague idea of what arthritis in general means” share with Douglas Unis, the associate orthopaedics professor at the Icahn School of Medicine at Mount Sinai (N.Y.) recently told Health magazine.

A new Canadian study, published in Arthritis Care & Research, finds that younger cohorts were likelier than prior generations to develop arthritis at a younger age, and that obesity plays a large role in patients’ tendency to develop arthritis.

Using data from nearly 9,000 people studied in the Canadian longitudinal National Population Health Survey (1994-2011), researchers examined four groups:

  1. World War II, or those born between 1935 and 1944
  2. Older baby boomers, born between 1945 and 1954
  3. Younger baby boomers, born between 1955 and 1964
  4. X, born between 1965 and 74

Their aim was to determine what impact, if any, birth cohort has on patients’ tendencies to develop arthritis and the degree to which it is associated with risk factors over time. In addition to analyzing patients’ ages, the researchers also considered risk factors, including years of education, household income, whether patients smoke, their frequency of physical activity, and their body mass index (BMI).

“In every cohort, it seems that the benefits of societal changes in increasing income, education, and smoking cessation on potentially reducing the prevalence of arthritis have been largely offset by the effect of increasing obesity over time,” the researchers noted, as quoted in MedPage Today. “In other words, had it not been for the increasing prevalence of obesity over time, the prevalence of arthritis might have declined in all cohorts, with the corollary that our understanding of the impact of BMI on arthritis prevalence trends is likely to be an underestimate.”

With each generation, the odds of developing arthritis increased. The odds ratio for developing arthritis among the 2,208 older baby boomers was 1.48; it climbed to 2.14 among the 2,781 younger baby boomers; and it increased yet to 3.2 for the 2,230 Gen. X patients. Those who were severely obese were two-and-a-half times likelier to report arthritis than those with a normal body mass index.

The researchers also found that those with higher education and income levels were less likely to report arthritis, and that smokers reported higher arthritis levels than non-smokers.