Smoking - Smoking seems to have adverse effect on telomeres, shortening their length. Studies have found that the telomere attrition caused by smoking one pack of cigarettes a day for a period of 40 years is equivalent to 7.4 years of life.Health Care Professional Diet Oxidative stress caused by smoking is mainly responsible for telomere attrition, resulting in their shortening.
Obesity - Obesity is also associated with increased oxidative stress and DNA damage. Studies show that the excessive loss of telomeres in obese individuals may be equivalent to 8.8 years of life, an effect which seems to be worse than smoking.
Environmental pollution - Exposure to traffic and industrial pollution can adversely affect telomeres. Reduction of the length of telomeres in a person is intimately related to numbers of years and severity of exposure to environmental pollution.
Stress - The stress is associated with release of glucocorticoid hormones by the adrenal glands, which cause increased oxidative damage to DNA and accelerated telomere shortening.