CANCER is one of the leading causes of death worldwide, and its incidence has been steadily rising. While genetics and environmental factors play a role, modern research increasingly shows the LIFESTYLE choices are among the most important contributors to many types of cancer. The World Health Organisation (WHO) estimates that 30-50% cancers could be prevented through healthy lifestyle changes.
Understanding how lifestyle influences cancer risk can help individuals take preventive steps and reduce their chances of developing the disease.
Cancer occurs when cells in the body grow uncontrollably due to mutations in their DNA. These mutations can be caused by several factors: Genetic inheritance; Environmental exposures (radiation, pollution); Infections (HPV, hepatitis0; and Lifestyle habits.
Among these, lifestyle is considered a modifiable risk factor, meaning individuals can change their behaviour to reduce risk.
What are lifestyle factors which can cause cancer?
1 Tobacco Use: The Biggest Lifestyle Risk.
Smoking is the single largest preventable cause of cancer. Tobacco is linked to cancers like- Lung cancer; Mouth and throat cancer; Esophageal cancer; Bladder cancer; Pancreatic cancer; and kidney cancer.
Tobacco smoke contains more than 70 carcinogenic chemicals. These substances damage DNA and trigger mutations that can lead to cancer. According to studies:
- About 85-90% of lung cancer cases are related to smoking.
- Even secondhand smoke increases cancer risk.
In our country, chewing tobacco and gutka also significantly increase the risk of oral cancer.
2 Unhealthy Diet and Cancer
Diet plays a major role in cancer development. Risk factors in diet are: High consumption of processed meat (sausages, bacon); Excess red meat; High-fat and high-sugar foods; and Low intake of fruits and vegetables.
Processed meat contains nitrosamines, chemicals linked with colorectal cancer.
A diet lacking antioxidants and fiber reduces the body’s ability to fight oxidative stress and inflammation, both of which can promote cancer.
3 Obesity and Physical Inactivity
Cancers associated with obesity are- Breast cancer (especially after menopause); Colon cancer; Liver cancer; kidney cancer, Pancreatic cancer; and Endometrial cancer.
Excess body fat affects the body in several ways- Increases inflammation, raises insulin and hormone levels, and alters metabolism. These changes can stimulate abnormal cell growth.
Lack of physical activity further increases the risk of contributing to weight gain and metabolic imbalance.
4 Alcohol Consumption
Cancers linked to alcohol are- Liver cancer; Breast cancer, Esophageal cancer; Mouth and throat cancer,; and Colorectal cancer.
Alcohol damages tissues and produces acetaldehyde, a toxic compound that can damage DNA.
Risk increases with frequency and quantity of alcohol consumption.
5 Lack of Sleep and Chronic Stress
Although research is ongoing, evidence suggests that chronic stress and poor sleep patterns may indirectly increase cancer risk.
Possible mechanisms include- Weakened immune system; Hormonal imbalances, and Increased inflammation.
Night shift work and irregular sleep cycles can also disrupt circadian rhythms, which may influence cancer risk.
6 Environmental and Occupational lifestyle Exposure
Certain lifestyle-related environments expose people to carcinogens like- Air pollution; Industrial chemicals; pesticide; Radiation exposure; and long-term sun exposure (UV radiation)
For example-Skin cancer is strongly linked to excessive UV radiation; and Mesothelioma is linked to asbestos exposure.
7 Infections Related to Lifestyle
Some infections linked to lifestyle behaviours can increase cancer risk. Examples include- HPV (Human Papillomavirus)-cervical cancer; Hepatitis B & C- Liver cancer; and Helicobacter pylori-stomach cancer.
Unsafe sexual practices and poor hygiene can increase exposure to these infections.
Research suggests that lifestyle factors contribute to a large proportion of cancers. Approx estimates are:
- Tobacco use: 22-25% of cancer deaths
- Obesity and diet: 10-20%
- Alcohol: 5-7%
- Physical inactivity: 5%
Preventing Cancer Through Lifestyle Changes
Adopting healthier habits can significantly reduce cancer risk
Key Preventive Steps
1 Quit tobacco completely-Avoid smoking, chewing tobacco, and exposure to secondhand smoke.
2 Maintain a healthy diet– Eat more fruits and vegetables; reduce processed and red meat; and Increase whole grains and fiber.
3 Exercise regularly-At least 150 minutes of moderate physical activity per weak.
4 Maintain healthy weight.
5 Limit alcohol intake.
6 Protect yourself from the sun-Use sunscreen and avoid excessive UV exposure.
7 Get Vaccinated– Vaccines such as HPV and Hepatitis B can prevent cancer-causing infections.
8 Regular screening – Early detection through screening (Mammography, Colonoscopy ,Pap smear) can prevent advanced cancer.
I the end, lifestyle is one of the most important and preventable contributors to cancer. While genetic factors can not be changed, many lifestyle habits can be modified to significantly reduce risk.
Anil Malik
Mumbai, India
11th March 2026