|Ahead of print publication
Prevalence of primary knee osteoarthritis in the urban and rural population in India
Rohit Yadav1, Ajay Kumar Verma2, Arjun Uppal1, Hemant Singh Chahar1, Jaydeep Patel1, Chandra Prakash Pal1
1 Department of Orthopaedic Surgery, Sarojini Naidu Medical College, Agra, India
2 Department of Orthopaedic Surgery, Motilal Nehru Medical College, Prayagraj, Uttar Pradesh, India
|Date of Submission||08-Dec-2020|
|Date of Acceptance||07-Jan-2022|
|Date of Web Publication||13-Jul-2022|
Chandra Prakash Pal,
Department of Orthopedics, Sarojini Naidu Medical College, Agra - 282 003, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
Introduction: Osteoarthritis (OA) is one of the most common causes of pain and disability, representing a significant burden for the individual and for society. The knee is one of the most prevalent among all joint sites affected by OA. The aim of this study is to analyze the prevalence of primary knee OA in the urban and rural population in India.
Methods: The study was a community-based cross-sectional study. The target population was from 5 metropolis (big cities), 5 small cities near the metropolis, 5 towns, and 25 villages from blocks of these towns, i.e., 5 sample groups were covered. We got a minimum sample size (n) = 4680 which was further divided into five sites equally (936 from each site). This was rounded to a sample of 1000 from each site. Data were collected by structured questionnaires, interviews, and observation of clinical and radiological findings. OA was graded using the Kellegren and Lawrence Scale.
Results: The overall prevalence of primary knee OA in big cities was 33.2%, 19.3% in small cities, 18.3% in towns, and 29.2% in villages. In the current study, it was seen that 32.7% of the population in the big city had a sedentary lifestyle as compared to 28.7% in villages and 18.1% in towns. About 44.5% of the population in the village had physically demanding work as compared to cities and towns.
Conclusion: The prevalence of symptomatic primary OA knee in urban areas is much higher than reported from rural regions. To guide the distribution of health-care resources and preventive strategies in future, our findings will be useful.
Keywords: Osteoarthritis, rural population, urban population
| Introduction|| |
Osteoarthritis (OA) is one of the most common causes of pain and disability, representing a significant burden for the individual and for society.,, Since incidence and prevalence increase with age, longer life expectancy will result in an increase in OA in future., Patients having primary OA usually present to us with pain, especially after activity and bearing the weight for a long period, and present with stiffness after prolonged inactivity. The knee is one of the most prevalent among all joint sites affected by OA. The knee is a weight-bearing joint that is essential for daily routine work and frequently associated with more reported pain in OA.,, Knee OA diagnosis is based on radiographic changes and clinical examination. According to recent recommendations, besides the radiographic evaluation, symptoms were also considered the most useful in the identification of OA patients. Pain is the main symptom because of which patients with knee OA came to the hospital. It is correlated with radiographic symptomatic changes, strongly associated with other signs and symptoms, and reliably predicts future disability., In the global burden of diseases 2000, OA was the fourth-leading cause of Years of healthy life lost due to disability (YLD) leading to 3% YLD. It is necessary to diagnosis early and intervenes timely to minimize the consequences of knee OA. In addition, treatment strategies in knee OA are frequently focused on pain relief and control. There are quite a lot of studies on the prevalence and determinants of knee OA. The aim of this study is to find cases with relevant knee OA and how this varies among the urban and rural populations.
The aim of this study is to analyze the prevalence of primary knee OA in urban and rural population.
| Methods|| |
The study was a community-based cross-sectional study. The study was approved by the institutional ethical committee of Sarojini Naidu Medical College, Agra (Approval number-2012/07, date of approval-December 21, 2012). The study was done across 5 sites in India namely Pune, Agra, Bangalore, Kolkata, and Dehradun. The target population was from 5 metropolis (big cities), 5 small cities near the metropolis, 5 towns, and 25 villages from blocks of these towns., i.e., 5 sample groups were covered– each sample group will comprise one metropolis, one small city, one block headquarters (town), and 5 villages from that block.
The WHO technical report series-919 “the burden of musculoskeletal conditions at the start of the new millennium” which contains the Bhigwan COPCORD data on the prevalence of rheumatoid arthritis (RA) and OA among the Indian population was used for sample size calculation. The estimated prevalence was 5.5% according to the study. Thus, we considered this as “p” in the following formula for calculating sample size. n = (t2 × P [100 − P]/m2), where n = required sample size, t = confidence level at 99% = value 2.58 rounded to 3, P = estimated prevalence (%) =5.5, m = margin of error (20% of p) = 1.1 Substituting all these values we get, Sample size n = 3866 = rounded to 3900. Adding a 20% no-response rate to this we got a minimum sample size of n = 4680 which was further divided into 5 sites equally (936 from each site). This was rounded to a sample of 1000 from each site. The total sample size was 5000, split evenly across the five sites. Each site was further divided into categories such as big city, small city, town and village, to get a proper representation of the population. Sample from each division was decided as per the population of the area.
This evaluation study was conducted using the household as the primary sampling unit for the quantitative survey. The respondents for the study were >40 years. One respondent from each household was selected based on the last birthday method. Exclusion criteria defined in the study were participants who had RA, inflammatory arthritis, bilateral end-stage knee OA, unable to walk without aids (single cane), SLE, polyarthralgia, any other surgical or medical condition that severely limits subjects functional ability.
Quantitative data were collected using a structured questionnaire and X-ray investigation. The structured questionnaire consisted of the following sections– Informed consent, demographic profile (age, sex), socioeconomic profile (education, occupation, income, housing conditions, type of work and lifestyle-related information), physical parameters (height, weight), family history about OA and osteoporosis, respondents history related to OA. This was followed by radiographs of both the knee joints in two views– an anterior-posterior view and a lateral view. OA was graded using the Kellegren and Lawrence scale for OA (1 = No osteophytes, normal joint space; 2 = Doubtful narrowing, possible osteophytes; 3 = Minimal but definite osteophytes, joint space; 4 = Definite and moderate osteophytes joint space narrow, some subchondral sclerosis). Kellgren-Lawrence grading 1 was considered subthreshold for OA. Grade 2 and 3 were considered as positive findings for primary knee OA.
We classified rural-urban population on basis of the following:
- A metropolis (big city) is a large city that is a significant economic, political, and cultural center for a country or region, and an important hub for regional or international connections, commerce, and communications
- Small cities, which have a population of at least 50,000 inhabitants in contiguous dense grid cells (>1500 inhabitants per km2)
- A town is larger or more populated than a village and smaller than a city
- Villages, which consist mostly of low-density grid cells.
- Urban–minimum population of 5000 people with population density at least 400 persons per square and 75% of the male population engaged in nonagriculture work (metropolis or big city and small city)
- Rural-the census bureau defines rural as any population, housing, or territory not included in an urban area (town and villages).
We also classified the physical activity of the population on the following basis:
- Sedentary work is work that involves very limited amounts of physical activity
- An active lifestyle means you do physical activity throughout the day. Any activity that gets you up and moving is part of an active lifestyle. Physical activity includes exercise such as walking or lifting weights. It also includes playing sports
- Physically demanding jobs include general physical activities, handling and moving objects, spending significant time standing, or having any highly physically demanding work. Highly physically demanding jobs involve such elements as dynamic or trunk strength or kneeling or crouching.
If body mass index (BMI) is <18.5, it falls within the underweight range. If BMI is 18.5 to <25, it falls within the healthy weight range. If BMI is 25.0 to <30, it falls within the overweight range. If BMI is 30.0 or higher, it falls within the obesity range.
Data analysis was performed using SPSS statistical software (SPSS Inc. Released 2008. SPSS Statistics for Windows, Version 17.0. Chicago: SPSS Inc). Frequencies and percentages were calculated to find the prevalence of primary knee OA. A Chi-square test was used to find the association of primary knee OA with various factors.
| Results|| |
The cross-sectional study covered all socioeconomic areas. The target population was from 5 metropolis (big cities), 5 small cities near the metropolis, 5 towns, and 25 villages from blocks of these towns, i.e., 5 sample groups were covered– each sample group will comprise one metropolis (big cities), one small city, oneblock headquarters (town), and 5 villages from that block.
The overall prevalence of primary knee OA in big cities was 33.2%, 19.3% in small cities, 18.3% in towns, and 29.2% in villages [Figure 1].
|Figure 1: Category-wise overall prevalence of primary knee osteoarthritis for sample|
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Agra had 1000 participants, of which 30.4% were from big city and 33.4% from the village. Small city and town consisted of 21.9% and 14.3% of participants. Of the 1000 participants (35.5%) were diagnosed with primary knee OA using radiography [Figure 2]. The prevalence of primary knee OA was highest in big city (32.2%) followed by villages (29.7%) [Figure 3].
|Figure 3: Prevalence of primary knee osteoarthritis in big city, small city, town, and village at different sites (numbers and percentages)|
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Pune had 35.8% of its participants in the big city, 24.3% in town, and 20.3% in village and 19.5% in small city. The prevalence of primary knee OA in the study population was 21.7% [Figure 2]. The prevalence of primary knee OA was 23.5% in town, 23.2% in village, followed by big city and small city (20.4% and 20.5%) [Figure 3].
Kolkata had 33.9% of its participants lived in big city and 34.1% in village, 17.5% in small city and 14.4% in village. Prevalence of primary knee OA in Kolkata measured up to 32.7% [Figure 2]. It was observed that the prevalence of primary knee OA was highest in town (37.8%) as compared to big city (31.8%), small city (28.7%), and village (33.6%) [Figure 3].
Bangalore had 38.8% of its population in the big city, 23.3% in small city, and 19.7% in town and 18.2% in village. The prevalence of primary knee OA in the study population was 26.6% [Figure 2]. The prevalence of primary knee OA was 37.6% in small city, 30.3% in town, followed by big city and village at 23.1% and15.8%, respectively [Figure 3].
The prevalence of primary knee OA in Dehradun was 27.2% [Figure 2]. The prevalence of primary knee OA was 29.3%, 29.1%, and 27.9%, respectively, in big city, small city and village and 17% in town [Figure 3].
Primary OA of the knees was found to be more prevalent in females (31.6%) than in males (28.1%). This finding is statistically significant (P = 0.007). The study found that the prevalence of OA knees increased with an increase in BMI. Primary knee OA prevalence was significantly (P = 0.007) low in underweight people (28%) as compared to normal weight and obese participants (33%). Prevalence was found to be highest in people who are overweight and/or obese. The prevalence was highest among the age group of 60 and above and lowest in people in the age group of 40–50 years (P = 0.001).
In the current study, it was seen that 32.7% of the population in the big city had a sedentary lifestyle as compared to 28.7% in villages and 18.1% in towns. About 44.5% of the population in the village had physically demanding work as compared to cities (34.6%) and towns (20.9%) [Table 1].
| Discussion|| |
There are several studies on the prevalence and determinants of knee OA but very little work has been done to find out the prevalence of primary knee OA in rural and urban population. The aim of this study is to find out the burden of primary knee OA in rural and urban areas separately. The present study shows the overall prevalence of primary knee OA was 28.7%. However, the prevalence of OA varied slightly with individual sites. The present study shows that the prevalence of OA knee was more in cities as compared to towns and villages. The prevalence of OA was highest in the big cities and villages of Agra and Kolkata. However, in Bangalore prevalence of OA was more in small city as compared to big city and village. There are many studies, which prove that OA is seen more in urban populations than in rural populations. The current study also proves the same. The COPCORD study showed a higher prevalence in urban as compared to the rural prevalence of OA in Bangladesh. A population-based cross-sectional survey done in rural china (Wuchuan County and Inner Mongolia) the prevalence of symptomatic knee OA in rural areas of China is much higher than reported from urban regions of China. In an observational study done in the rural Tibetian region prevalence of knee pain was 25% and significantly associated in 50 years as compared to younger people. Similarly, a study done by Muraki et al., on the Japanese population symptomatic radiographically confirmed knee OA cases was evidenced to have a higher prevalence in two mountain regions as compared to the rural and urban populations. A house to house survey done by Salvi et al. in South Delhi among 260 peri menopausal women, OA was found to be higher in lower socioeconomic than higher socioeconomic populations. A study done in Chandigarh had similar results lesser prevalence than this study.
Various studies show that OA knee is more prevalent in people with a sedentary lifestyle followed by physical demanding lifestyle and lowest in people who had fairly active physical active lifestyle. In our study, the same was statistically proved (P = 0.001). In the current study, it was seen that more number of participants in the big cities had a sedentary lifestyle as compared to in villages and in towns which may be one of the reasons for the high burden of primary OA in the urban population.
This study shows that increasing age, female sex, and obesity to be associated with an increased risk of knee OA. The number of obese patients in the study was 33% and found that these people were more likely to have OA of the knee joint. Silverwood et al. in their meta-analysis also found an increased risk of 2.1 times of knee OA in overweight (BMI 25–30 kg/m2) and obese (BMI > 30 kg/m2) individuals. Martyn et al. also found a positive correlation of knee OA with increased BMI. He also recommended that moderate physical activity may help in prevention as well as improve knee symptoms. In the current study, it was seen that the big cities have more number of obese and overweight participants as compared to small cities and towns which may be one of the reasons for the high burden of primary OA in the urban population.
The present study has some limitations that should be considered when interpreting the findings. Since bilateral end-stage knee OA and unable to walk without aids (single cane OA) are excluded so true prevalence may be underestimated. Since the study recorded the current level of physical activity, it may be possible of having knee OA that may be more due to age rather than lifestyle. Furthermore, because the study did not utilize a prospective (longitudinal) cohort design, it would be difficult to speculate on the long-term impact of physical activity, habits, and lifestyles on the prevalence of knee OA.
| Conclusion|| |
The prevalence of symptomatic primary knee OA in urban areas is much higher than reported in rural regions. A sedentary lifestyle may be the major associated factor for the increase in the number of primary knee OA patients in the urban population. Lifestyle modification and behavioral changes must be encouraged. A longitudinal cohort study can be planned which will, in the long run, prove the impact of physical activity, habits, and lifestyles. To guide the distribution of health-care resources and preventive strategies in the rural and urban population in future, our findings will be useful.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]