Risk Factors of Osteoarthritis – A Hospital Based Case Control Study

Manoj Kumar S,a Asha K P,b Indu D,b Jeethu T J,c Karthika Vikram,c Manju Surendranc

a. Department of Orthopaedics, Medical College Trivandrum; b. Department of Community Medicine,  Medical College Trivandrum; c. Medical Students, Medical College Trivandrum

Osteoarthritis is a chronic progressive musculoskeletal disorder involving the joints, affecting mainly middle aged and elderly.  It causes considerable morbidity and affects daily life activities.  This study aimed to find out the risk factors of Osteoarthritis among patients attending orthopaedic department at Medical College Trivandrum.  An unmatched case control study was conducted in the Department of Orthopaedics, Medical College Trivandrum.  50 patients diagnosed to have osteoarthritis were included as cases and 50 patients who had come for other diseases were taken as controls.  Data was obtained by interview method using a semi structured questionnaire.  Statistical analysis was done using chi-square test.  Obesity (P value<0.001, OR-11.3), family history of osteoarthritis (P value<0.03, OR-4.04), history of trauma (P value<0.001, OR-17.25) and history of fracture (P value<0.014, OR-5.5) were found to be associated with increased risk of osteoarthritis.  This study helps in identifying the important risk factors of osteoarthritis which would help in providing insight into planning appropriate interventions.

Keywords: , ,

Background

Osteoarthritis is the most common form of arthritis.  It is a chronic progressive musculoskeletal disorder involving the joints, affecting mainly middle aged and elderly.  With increasing life expectancy, osteoarthritis is estimated to be the fourth leading cause of disability by the year 2020.1  With many Asian countries ageing rapidly, China and India are ranked the top two countries with absolute number of people aged 65 years and above at 106 and 60 million respectively.2 Osteoarthritis is fast becoming a major public health problem and an important cause of disability in developing countries.  Worldwide osteoarthritis is the sixth leading cause of years lived with disability.1  Osteoarthritis is associated with increasing pain and difficulty in performing day to day activities and also loss of economic productivity of individuals.  In Kerala, people above sixty years constitute 13% of the state’s population as compared to the national figure of 8.2% (Census 2011).  With not much data available on risk factors of osteoarthritis among Kerala population it is of utmost importance to identify the important risk factors associated with osteoarthritis and to develop effective preventive strategies to successfully deal with it.

Objective

To identify the risk factors of osteoarthritis among patients attending orthopaedic department at Medical College Trivandrum, Kerala.

Methods

This case control study was conducted in the Department of Orthopaedics, Medical College Trivandrum, which is a tertiary care centre in Trivandrum District.  50 Patients in the age group 40-65 years clinically diagnosed to have osteoarthritis attending orthopaedic department during the study period from September 2009 to November 2009 were included as cases and 50 patients attending the OP for other diseases were taken as controls.  Patients who are not willing to participate in this study and patients with congenital joint disease were excluded.  Clinical diagnosis was based on the presence of joint symptoms and evidence of structural change as seen on x-ray.  Data was obtained on study variables such as age, sex, obesity, habits like smoking, alcoholism, family history of osteoarthritis, previous history of trauma, history of fracture, systemic illness like diabetes, hypertension, and history of prolonged intake of drugs.   Informed consent was taken and data was collected by interview method using a semi structured questionnaire.  Statistical analysis was done using Chi-Square test and odds ratios were calculated.

Table 1. Distribution of Study Variables

Table 1. Distribution of Study Variables

Results

In this study, 50 patients diagnosed to have osteoarthritis were included as cases and 50 patients who had come for other diseases were taken as controls.  More than two third of the study participants were females.  Obesity (P value<0.000, OR-11.3), family history of osteoarthritis (P value<0.03, OR-4.04), history of trauma (P value<0.000, OR-17.25) and history of fracture (P value<0.014, OR-5.5) were found to be risk factors of osteoarthritis (Table 1).  

Discussion

Osteoarthritis is the most common form of chronic arthritis affecting 250 million people worldwide.3  It is characterised by joint pain and impairment of mobility due to gradual wearing of cartilage.  Worldwide it causes moderate to severe disability in about 43.4 million people.4

Even though the cause of osteoarthritis is not fully understood it is thought to be due to genetic, biomechanical and environmental stresses.  The prevalence of osteoarthritis increases with age, and with the increase in growth of elderly population in India, it has become a major cause of disability.  Worldwide it is seen that in elderly population osteoarthritis is the most common articular disease.5  In a study conducted by MK Sharma, HM Swami et al,6 the prevalence of osteoarthritis among elderly was found to be 56.6%.

In this study, a significant association was found between obesity and osteoarthritis (P value<0.001, OR-11.3).  Obesity leads to high mechanical stress on the joints predisposing to osteoarthritis.  It seen that a force of  three times the body weight is transmitted across the hip and 3-6 times the body weight is transmitted across the knee during a single-leg stance in the gait cycle.  These forces are increased several times when an obese person walks leading to excess forces across the joints.10  In the Framingham study the BMI at study entry level predicted the presence of osteoarthritis of the knee 36 years later.  Studies by Karlson et al12 also found obesity to be a strong risk factor for osteoarthritis.

Family history of osteoarthritis (P value<0.03, OR-4.04) was found to be significantly associated with osteoarthritis in this study.  Other studies have also shown that genetics have a key influence on occurrence of osteoarthritis.  Family studies from early sixties have shown first-degree relatives at increased risk for osteoarthritis.7  Studies conducted by Bijkerk C et alalso found strong link between genetics and occurrence of osteoarthritis.  The Rotterdam study estimated 56% heritability in osteoarthritis of the hand.  A study by Valdes et al implicated genetic pathways in the occurrence of osteoarthritis.9

In this study, history of trauma (P value<0.001, OR-17.25) and history of fracture (P value<0.014, OR-5.5) were found to be significantly associated with osteoarthritis.  Studies by Felson et al10 reported injuries as an important risk factor in the development of osteoarthritis.

Injuries caused by high force events initiates inflammatory and metabolic imbalances of tissue tissue turnover compromising the mechanical properties of tissues leading to osteoarthritis.13  Studies by Frobell RB et al have shown that over 30% of patients with acute anterior cruciate ligament (ACL) or meniscal injuries develop radiographic knee OA within 5 years post-injury.14 

Conclusion

It is seen from this study that those with obesity and history of trauma have a higher odds for developing osteoarthritis when compared to others. Osteoarthritis being a chronic progressive disorder affecting the middle aged and elderly, it poses a substantial threat to the health of individuals and their quality of life, with serious socio-economic consequences.  As there is currently no cure for osteoarthritis, it has become important to reduce cartilage loss and the progression of this condition by raising awareness about prevention of osteoarthritis and taking steps to reduce the prevalence of modifiable risk factors of osteoarthritis like obesity and trauma.

References

  1. Woolf AD, Pfleger B. Burden of major musculoskeletal conditions. Bulletin of the World Health Organization. 2003;81 (9):646–56.
  2. Kinsella K, He W (2009) An Ageing World: 2008. U.S.Census Bureau, Washington, DC.
  3. Vos T, Flaxman AD, Naghavi M, Lozano R, Michaud C, Ezzati M, Shibuya K, Salomon JA, Abdalla S, Aboyans V, et al. (December 2012). “Years lived with disability (YLDs) for 1160 sequelae of 289 diseases and injuries 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010”. Lancet 380 (9859): 2163–96
  4. The Global Burden of Disease: 2004 Update. Geneva: World Health Organization. 2008. p. 35
  5. Gupta SJ. Osteoarthritis and obesity. Orthopaedics today.2001;3:137-41
  6. Sharma M, Swami H, Bhatia V, Verma A, Bhatia S, Kaur G. An epidemiological study of correlates of osteo-arthritis in geriatric population of UT Chandigarh. Indian Journal of Community Medicine. 2007;32(1):77.  doi: 10.4103/0970-0218.53414.
  7. Kellgren JH, Lawrence JS, Bier F. Genetic Factors in Generalized Osteo-Arthrosis. Ann Rheum Dis. 1963 Jul;22:237–55.
  8. Bijkerk C, Houwing-Duistermaat JJ, Valkenburg HA, Meulenbelt I, Hofman A, Breedveld FC, et al. Heritabilities of radiologic osteoarthritis in peripheral joints and of disc degeneration of the spine. Arthritis Rheum 1999; 42: 1729–35.
  9. Valdes AM, Spector TD. The clinical relevance of genetic susceptibility to osteoarthritis. Best Pract Res Clin Rheumatol. 2010 Feb;24(1):3–14.  doi: 10.1016/j.berh.2009.08.005.
  10. Felson DT. Weight and osteoarthritis. Am J Clin Nutr. 1996 Mar;63(3 Suppl):430S–432S.
  11. Gelber AC. Obesity and hip osteoarthritis: the weight of evidence is increasing.  Am J Med. 2003; 114(2):158-159
  12. Karlson EW, Mandl LA, Aweh GN, Sangha O, Liang MH, Grodstein F. Total hip replacement due to osteoarthritis: the importance of age, obesity, and other modifiable risk factors. Am J Med. 2003 Feb 1;114(2):93–8.
  13. Cattano NM, Barbe MF, Massicotte VS, Sitler MR, Balasubramanian E, Tierney R, Driban JB. Joint trauma initiates knee osteoarthritis through biochemical and biomechanical processes and interactions. OA Musculoskeletal Medicine 2013 Mar 01;1(1):3
  14. Frobell RB, Roos HP, Roos EM, Roemer FW, Ranstam J, Lohmander LS. Treatment for acute anterior cruciate ligament tear: five year outcome of randomised trial. BMJ. 2013;346:f232.

End Note

Author Informatiom

  1. Manoj Kumar S – Associate Professor, Dept of Orthopaedics, Medical College Trivandrum, Kerala
  2. Asha K P – Associate Professor, Dept of Community Medicine,  Medical College Trivandrum
  3. Indu D – Associate Professor, Dept of Community Medicine,  Medical College Trivandrum
  4. Jeethu T J, Karthika Vikram & Manju Surendran – Medical Students, Medical College Trivandrum

Conflict of Interest – None Declared

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