Risk factors associated with arthritis

Arthritis shares a number of risk factors with other chronic diseases, such as:

Non-modifiable risk factors

  • age
  • gender
  • genetic predisposition.

Modifiable risk factors

  • physical inactivity
  • smoking
  • overweight/obesity
  • poor diet (inconsistent with dietary guidelines)
  • occupation (involving manual labour or joint loading)
  • joint trauma and injuries.

These risk factors increase the chance of developing a chronic condition, affect quality of life and can complicate treatment and management options [1]. Managing these risk factors can help manage the progression and health burden of arthritis, and can reduce the risk of developing further complications and other chronic diseases.

The following analysis is based on people aged 18 and over. This age group was selected due to the available data in the ABS National Health Survey (NHS) and to ensure consistency with other AIHW risk factor reports [2,3].

The risk factors data presented here are a snapshot at one point in time, based on self-reported data from the NHS. Caution should be used in attributing cause and effect to self-reported risk factors and arthritis. Risk factors present at the time of the survey may or may not have contributed to the presence of arthritis. Similarly, the presence of arthritis should not be attributed to the number of risk factors a person has. When interpreting self-reported data, it is important to recognise that we rely on respondents providing accurate information, so the outputs may not reflect the true situation.

Common risk factors

According to the 2011–12 NHS, after adjusting for differences in age structure for people with and without arthritis, people with arthritis were more likely to be current smokers, physically inactive and obese, compared to those without arthritis (see Figure 1 and Table 1). Risk factor definitions are included in Box 1.

Figure 1: Prevalence of risk factors in people with and without arthritis, 2011–12

Arthritis risk factors fig1: prevalence of risk factors in people with and without arthritis PNG

Notes

  1. Rates are age-standardised to the Australian population as at 30 June 2001.
  2. The thin vertical lines attached at the end of each bar are 95% confidence intervals. We can be 95% confident that the true value is within this confidence interval.

Source: AIHW analysis of unpublished ABS Australian Health Survey, 2011–12 (National Health Survey Component) (Data tables).

Specific risk factors

Smoker status

After adjusting for age, people with arthritis were more likely to report to having been a smoker, with:

  • 23.1% being a current daily smoker (compared with 16.1% without this condition)
  • 32.6% being an ex-smoker (compared with 30.3% than without this condition).

Smoking is the main modifiable risk factor associated with rheumatoid arthritis, as it affects treatment with biologic agents [4]. Experts recommend avoiding smoking-smoking cessation appears to reduce the risk of developing rheumatoid arthritis over time [5].

Figure 2: Smoker status of people with and without arthritis, 2011–12

Arthritis risk factors fig2: smoker status PNG

Notes

  1. Rates are age-standardised to the Australian population as at 30 June 2001.
  2. The thin vertical lines attached at the end of each bar are 95% confidence intervals. We can be 95% confident that the true value is within this confidence interval.

Source: AIHW analysis of unpublished ABS ‘Australian Health Survey, 2011–12 (National Health Survey Component) (Data tables).

Physical activity

After adjusting for age, people with arthritis were significantly less likely than people without arthritis to report engaging in the recommended levels of moderate or vigorous physical activity. 21.0% of adults with arthritis reported being physically inactive (this includes people who are inactive and insufficiently active) compared to 17.5% of those without arthritis.

Physical activity can help decrease pain, improve function and reduce disability associated with all forms of arthritis. Additionally, physical activity can also help people with arthritis manage other chronic conditions such as diabetes, heart disease, and obesity [6].

Figure 3: Physical activity in people with and without arthritis, 2011–12

Arthritis risk factors fig3: physical activity PNG

Notes

  1. Rates are age-standardised to the Australian population as at 30 June 2001.
  2. The thin vertical lines attached at the end of each bar are 95% confidence intervals. We can be 95% confident that the true value is within this confidence interval.

Source: AIHW analysis of unpublished ABS Australian Health Survey, 2011–12 (National Health Survey Component) (Data tables).

Body weight

After adjusting for age, people with arthritis were 1.3 times as likely to report being obese than people without arthritis. Obesity increases the risk for developing rheumatoid arthritis, in particular for women [7]. Being overweight doubles a person's risk of developing knee osteoarthritis, while obesity increases the risk fourfold [8].

Figure 4: Proportion of people with and without arthritis by body mass index (BMI), 2011–12

Arthritis risk factors fig4: BMI PNG

Notes

  1. Rates are age-standardised to the Australian population as at 30 June 2001.
  2. The thin vertical lines attached at the end of each bar are 95% confidence intervals. We can be 95% confident that the true value is within this confidence interval.

Source: AIHW analysis of unpublished ABS ‘Australian Health Survey, 2011–12 (National Health Survey Component) (Data tables).

Age differences in risk factors in people with arthritis

The prevalence of risk factors in people with arthritis varied with age. Younger people with arthritis (aged 18–44) were more likely to report smoking (31.2%) than those aged 45 or over (13.0%). In contrast, people aged 45 or over were more likely to report being physically inactive (64.7% compared with 57.0% of people aged 18–44) or being overweight or obese (64.4% compared with 58.7% of people aged 18–44). A similar pattern is noted for the above risk factors in people in the general population.

Figure 5: Prevalence of risk factors in people with arthritis, by age, 2011–12

Arthritis risk factors fig5: risk factor prevalence by age PNG

 

Note: The thin horizontal lines attached at the end of each bar are 95% confidence intervals. We can be 95% confident that the true value is within this confidence interval.

Source: AIHW analysis of unpublished ABS Australian Health Survey, 2011–12 (National Health Survey Component (Data tables).

Box 1: Risk factors defined

Smoking

Smoker status is defined by the extent of regular smoking of tobacco at the time of interview. This includes manufactured (packet) cigarettes, roll-your-own cigarettes, cigars and pipes, at time of interview. It excludes chewing tobacco and smoking of non-tobacco products. The categories are:

Current daily smoker Regularly smoking one or more cigarettes, cigars or pipes per day
Current smoker (occasional) Smoking cigarettes, cigars or pipes less frequently than daily (weekly or less than weekly)
Ex-smoker Not currently smoking, but smoked daily, or at least 100 cigarettes, or pipes, cigars, etc. at least 20 times in lifetime
Never smoked Never regularly smoked daily, and smoking less than 100 cigarettes in the lifetime and/or smoking pipes, cigars, etc. less than 20 times in the lifetime.

Physical activity

Physical activity is defined as any bodily movement that requires energy expenditure. This includes walking (for transport, fitness, recreation, or sport). The categories include:

Inactive* Not doing physical activity (including walking for transport and fitness, and moderate and vigorous activity) in the week before interview.
Insufficiently active* Not completely inactive but failing to meet the requirement of at least 150 minutes of physical activity (including walking for transport and fitness, and moderate and vigorous activity) over five separate sessions in a given week. For the purpose of this measure, vigorous activity time is multiplied by a factor of two.
Sufficiently active for health Participation in at least 150 minutes of physical activity (including walking for transport and fitness, and moderate and vigorous activity) over five separate sessions in a given week.

*Physical inactivity

Not achieving the recommended amounts of physical activity of 150 minutes per week over at least five days. The analysis includes categories of inactive and insufficiently active.

Body weight

Based on body mass. Categories of body mass were derived from the body mass index (BMI)—calculated by dividing a person’s weight in kilograms by the square of their height in metres (kg/m2). The standard recommended by the World Health Organization to measure BMI for adults aged 18 and over is:

Classification BMI (kg/m2)
Underweight Less than 18.5
Normal weight range 18.5 to less than 25
Overweight 25 to less than 30
Obese 30 or more

Source: [9].

References

  1. Arthritis Australia 2014. Time to move: arthritis. Sydney: Arthritis Australia. Viewed 12 December 2014.
  2. AIHW (Australian Institute of Health & Welfare) 2015. Cardiovascular disease, diabetes and chronic kidney disease-Australian facts: Risk factors. Cardiovascular, diabetes and chronic kidney disease series no. 4. Cat. no. CDK4. Canberra: AIHW.
  3. AIHW 2013. Risk factors contributing to chronic disease. Cat No. PHE 157. Canberra: AIHW.
  4. Maska LB, Sayles HR, O'Dell JR et al. 2012. Serum cotinine as a biomarker of tobacco exposure and the association with treatment response in early rheumatoid arthritis. Arthritis Care & Research 64(12):1804–1810.
  5. Di Giuseppe D, Orsini N, Alfredsson L et al. 2013. Cigarette smoking and smoking cessation in relation to risk of rheumatoid arthritis in women. Arthritis Research and Therapy 15:R56.
  6. CDC (Centers for Disease Control and Prevention) 2010. A national public health agenda for osteoarthritis.
  7. Crowson CS, Matteson EL, Davis III JM et al. 2013. Contribution of obesity to the rise in incidence of rheumatoid arthritis. Arthritis Care & Research 65(1):71–77.
  8. Muthuri SG, Hui M et al. 2011. What if we prevent obesity? Risk reduction in knee osteoarthritis estimated through a meta-analysis of observational studies. Arthritis Care & Research; 63(7):982–990.
  9. ABS (Australian Bureau of Statistics) 2014. Australian Health Survey. Viewed on 15 October 2014.