Understanding How Obesity Can Impact Your Bone and Joint Health

While it is well-known that Obesity increases the risk of heart disease, Stroke, Diabetes, and some cancers, knowledge about its effect on bone and joint health amongst the public is limited.

Obesity is a condition in which a person has an excessive amount of body fat or an unhealthy body fat distribution. Not only does Obesity make physical movement challenging, but it also raises the risk for numerous health complications. In addition, excess body fat puts strain on the joints and multiple organs in the body. It also causes various changes in hormones and metabolism, thereby increasing inflammation in the body.

The World Health Organization (WHO) defines Obesity using the Body Mass Index (BMI), which is a ratio of one’s body weight in kilograms to the square of their height in metres (kg/m2). An individual is classified as being ‘overweight’ if their BMI is ≥ 25 and ‘obese’ if their BMI is ≥ 30. According to WHO’s 2016 statistics, 39 per cent adults worldwide were overweight, and 13 per cent were obese. The scourge of obesity has tripled since 1975.

In the past two or three decades, there has been a drastic change in dietary habits, including increased consumption of high fat and sugar-rich foods on the one hand and decreased physical activity on the other hand. These two factors have led to Obesity becoming a major health issue around the globe. While it is well-known that Obesity increases the risk of heart disease, Stroke, Diabetes, and some cancers, knowledge about its effect on bone and joint health amongst the public is limited.

Effects on Joint Health:

Osteoarthritis (OA) and Rheumatoid Arthritis (RA) are the two most familiar conditions affecting the joints. Osteoarthritis is characterised by joint damage due to wear and tear, while Rheumatoid Arthritis is an autoimmune disease where the body’s immune system attacks its joints and other tissues. Obesity is linked to both OA and RA.

Obesity and Osteoarthritis

The effect of Obesity on joint degradation is two-fold, including physical and chemical. The mechanical overload due to obesity increases the risk of cartilage degeneration, especially in the weight-bearing joints like knees and hips (physical effect). Additionally, the fat tissue in the body produces certain chemicals, which also results in cartilage damage (chemical effect). Research has shown that obese people have an increased risk of OA affecting the knees, hips, wrists, and hand joints.

Obesity and Rheumatoid Arthritis: 

In Rheumatoid Arthritis, the damage to the body’s joints and tissues is mediated by cytokines. The fat tissue in obese individuals also produces and releases cytokines which causes inflammation in the joints. Obesity increases the risk of RA, reduces the chance of disease remission, and adversely affects treatment outcomes.

Obesity and Bone Mass: 

The relationship between Obesity and bone mass is complex. Osteoporosis is characterised by loss of bone mass, which makes the bones brittle and increases the risk of fractures. Earlier research suggested that increased body fat resulted in increased bone mass. This was attributed to increased mechanical loading of bone in obese people and increased Estrogen production in fat tissue, which has a protective effect on bone mass. Obesity was deemed to be protective against hip fractures. However, newer evidence, based on more robust research methodology, confirmed that increased body fat resulted in lower bone mass and may also increase the risk of fractures.

In conclusion, Obesity adversely affects bone and joint health and is the leading cause of physical disability. Regular physical activity and healthy food habits will help tackle Obesity, especially if implemented from a young age. In certain instances, hormonal and metabolic factors may also lead to Obesity. For such cases, appropriate medical guidance and treatment can help treat the causes of Obesity. Keeping a check on your body weight will help protect all the body systems and promote general health and well-being.

(Inputs by Dr Siddharth M. Shah, Consultant Orthopedics and Joint Replacement Surgeon, SL Raheja Hospital, Mahim – A Fortis Associate)