Effect of cigarettes on passive smokers

Question

I have heard even passive smokers are subjected to many health issues even though they don't smoke directly. What are the issues related to health that can occur in the passive smokers, and does it includes any long term effects on health?

Answer 1

Passive (or secondhand) smoking can increase your risk of cancer and other health problems. Inhaled smoke is a mixture of smoke from the burning end of a cigarette or cigar and the smoke exhaled from the lungs of smokers. It is harmful and may cause a wide range of adverse health effects, particularly harmful for children.

Studies show that non-smokers exposed to second-hand smoke are at risk for many of the health problems associated with direct smoking.

Children who breathe in secondhand smoke have an increased risk of:

• cot death (sudden infant death syndrome, or SIDS) – this is twice as likely in babies whose mothers smoke^{wiki, NHS},
• lung infections^{1999, 2003, 2003, 2004},
• impaired respiratory function and slowed lung growth²⁰⁰⁷,
• developing asthma – smoking can also trigger asthma attacks in children who already have the condition^NHS,
• allergies,
• Crohn's disease²⁰⁰⁷,
• serious respiratory (breathing) conditions such as bronchitis and pneumonia – younger children are also much more likely to be admitted to hospital for a serious respiratory infection,
• meningitis,
• coughs and colds,
• a middle ear infection (otitis media), which can cause hearing loss²⁰⁰⁸,
• learning difficulties, developmental delays, and neurobehavioral effects^{1996, 2008},
• an increase in tooth decay²⁰⁰⁸.

^{Source: Is passive smoking harmful? at NHS and Wikipedia}

For adults this includes:

• cancer,
  • lung cancer,
  • breast cancer,
  • brain tumor,
• risk of ear infections,
• cardiovascular disease:
  • risk of heart disease,
  • reduced heart rate variability,
  • higher heart rate,
  • increased risk of atherosclerosis²⁰⁰⁹,
• respiratory disease such as lung problems and risk of asthma,
• cognitive impairment and dementia,
• during pregnancy can cause:
  • low birth weight,
  • premature birth,
  • damage to children's carotid arteries at birth and at age 5²⁰¹²,
  • higher risks of delivering a child with congenital abnormalities, longer lengths, smaller head circumferences, and low birth weight²⁰¹⁰,
• skin disorders (such as Atopic dermatitis)²⁰¹¹,
• worsening of asthma, allergies, and other conditions²⁰⁰⁴,
• increased risk of death^{1991, 1992}.

In 2003, IARC and WHO reviewed all significant published evidence related to tobacco smoking and cancer and concluded:

These meta-analyses show that there is a statistically significant and consistent association between lung cancer risk in spouses of smokers and exposure to second-hand tobacco smoke from the spouse who smokes. The excess risk is of the order of 20% for women and 30% for men and remains after controlling for some potential sources of bias and confounding.

Other studies confirmed these findings, such as study from 2007 by American Journal of Public Health which claim^{2004, PDF}:

A strong relationship was observed between lung cancer and duration of exposure to environmental tobacco smoke. The findings provide the strongest evidence to date that exposure to environmental tobacco smoke in the workplace is associated with an increased risk of lung cancer.

^{Image credits: CDC}

See also:

• Passive smoking: Effects at Wikipedia
• Health effects of smoking during pregnancy

Answer 2

According to The Better Health Channel (independant of any business, funded by the State Government of Victoria, Australia), passive smokers are exposed to many health risks that include long-term effects.

To make it short:

Second-hand smoke is a danger to everyone, but children, pregnant women and the partners of people who smoke are most vulnerable. Passive smoking increases the risk of sudden infant death syndrome (SIDS or cot death), middle ear disease, asthma, respiratory illnesses, lung cancer and coronary heart disease.

People who have never smoked who live with people who do smoke are at increased risk of a range of tobacco-related diseases, including lung cancer, heart disease and stroke.

The full explanation (and list of risks depending on subjects) is available here on the BHC website.