A Canadian Study in Arthritis Care & Research concludes that young generations are reporting arthritis at an earlier age. The authors of the study believed it is linked to rising obesity rates.
The study looked at arthritis incidence in four different groups:
- The World War II group (1935-1944) is the benchmark group.
- The generation Xers (1965-1972), where the odds ratio for arthritis was 3.20.
- The younger baby boomers (1955-1964), where the odds ratio for arthritis was 2.14.
- The older baby boomers (1945-1954), where the odds ratio for arthritis was 1.48.
The study was conducted by Elizabeth Badley, PhD, of the Dalla Lana School of Public Health at the University of Toronto, and her colleagues. Bailey and her team found that severely obese people were 2.5 times more likely than people with a normal body mass index (BMI).
The study looked at the 8,817 results from the Canadian longitudinal National Population Health Survey (NPHS) from 1994 to 2011. The NPHS data were grouped into four birth cohorts: World War II (1,598), older baby boomers (2,208), younger baby boomers (2,781), and generation X (2,230). Besides the data collected from the NPHS questionnaires administered every 2 years, the authors of the study also looked at self-reported chronic conditions, like arthritis, that had been diagnosed by a healthcare professional.
In all the cohorts, the proportion of people who reported arthritis increased from 1994 to 2011. Below are the findings from the study:
- More recent cohorts had successively greater prevalence of arthritis.
- Significant cohort-BMI and age-BMI interactions indicated an earlier age of arthritis onset for obese individuals than those of normal weight.
- People with higher education and income were less likely to report arthritis.
- Non-smokers were less likely to report arthritis than people who currently smoked.
- Overall, if not for the increasing prevalence of obesity over time, the prevalence of arthritis might have declined.
Other factors that may have played a role in the outcomes of the study include: increased health literacy and increased levels of physical activity and exercise. Furthermore, active people are better managing their joint symptoms or exercise-related musculoskeletal injuries, which can lead to osteoarthritis.
The authors concluded: "The generational differences show that arthritis education needs to reach young and middle-aged adults. Not only was the cohort effect of higher arthritis prevalence more marked in those who were obese compared to those of normal weight, in all cohorts the age of onset of arthritis in obese individuals was earlier. This has implications for the targeting of public health messages for the control and management of arthritis."
Study limitations are related to self-reporting and participant dropouts and deaths. The NPHS questionnaire also asked about arthritis in general, while findings could reflect osteoarthritis, common amongst the study participants.