Children and Secondhand Smoke Risks Decades After Exposure

Health Professional, Medical Reviewer

Researchers at the American Cancer Society (ACS) looked at the risk of children exposed to secondhand smoke and health consequences later in life as part of the Cancer Prevention Study-II (CPS-II) cohort.

They recruited people ages 50 to 74 during 1992-1993. These participants were followed for 22 years. An initial questionnaire was filled out when the participants first signed on and they were then asked to complete the same questionnaire every two to three years. Exposure to secondhand smoke was defined in the study as exposure to smoke for more than 10 hours per week before age 16.

Most of the participants were born in the 1930’s and 40’s when smoking was socially acceptable and also quite likely to occur in front of children, specifically in the home setting.

They looked at older adults who had never smoked cigarettes but did have exposure to parental smoking. In that arm of the study it was found that growing up in a household where there was a daily smoker, was associated with 31 percent higher likelihood of death from COPD later in life.

It has been established that children exposed to secondhand smoke have an increased risk of asthma and also experience more frequent exacerbations. This research is the first effort to explore what happens to kids later on in life if they experienced secondhand smoke exposure.

The results of this research are considered reliable given the large number of patients studied (over 70,000) and the length of time that the individuals were followed (over two decades).

The Centers for Disease Control and Prevention (CDC) has published a position statement on the health effects of secondhand smoke. Some of its main points include:

  • Since the 1964 Surgeon General’s Report, there were 2.5 million deaths among non-smokers due to secondhand smoke.

  • The effects of secondhand smoke on children include more severe asthma attacks, respiratory infections and risk of sudden infant death syndrome (SIDS).

The second report issued by the Surgeon General, twenty years after the initial report, established the fact that although rates of smoking declined, there was an increase in the number of persons exposed to secondhand smoke. They were referred to as “involuntary smoking” participants with health consequences from involuntary smoking.

The second report in the 1980s showed that secondhand smoke was associated with 34,000 premature deaths from heart disease, increased risk of stroke by 20-30 percent, and it identified that secondhand smoke was associated with 7,300 lung cancer deaths among non-smokers.

The effects of secondhand smoke in causing cancer has been addressed by the U.S. Environmental Protection Agency (EPA) and the International Agency for Research on Cancer (IARC). Both agencies have classified secondhand smoke as a known human carcinogen.

The agencies further state that there is no safe level by which one is precluded from developing cancer in the future. Separating smokers from non-smokers and eliminating smoking in all enclosed and indoor spaces are the only ways to fully protect non-smokers.

It’s important to note that cleaning the air and ventilating buildings cannot completely eliminate exposure to secondhand smoke that occurs within those confines.

Secondhand smoke exposure occurs in two different forms:

Mainstream smoke - This is the smoke exhaled by a smoker.

Sidestream smoke - This is smoke from the lighted end of a cigarette, pipe, cigar or hookah. This type of smoke apparently has higher concentrations of carcinogens and produces smaller particles, which makes this more dangerous type of smoke.

Up until this point most studies outlining the risks of secondhand smoke examined current exposure in adults. The significance of this research study is that it’s the first time that a study addressed past secondhand smoke exposure during childhood and the effect it had on health later in life.

The researches feel that understanding these long-term effects is even more relevant in countries where smoking and exposure to secondhand smoke is much higher. That would include Eastern European countries, South Korea, Kazakhstan, and Japan. America ranks in the middle.

Some important points to consider:

  • Children have developing lungs and other organ systems. An environment where there are irritating elements that can cause cellular alteration could result in a new generation of cells that are not normal and that potentially will continue to multiply and possibly result in serious health implications including cancer.

  • The fact that children during their growth phase have higher turn over of cells can augment the effects of cellular alteration.

  • The inflammatory process that is triggered by lungs exposed to irritant smoke can affect organs other than the lungs. This may explain the higher than normal rate of cardiovascular disease and stroke described in the U.S. Surgeon General’s report among those individuals exposed to secondhand smoke during childhood.

  • Symptoms of secondhand smoke exposure in kids are not as obvious as those in adults which is why the active inflammatory process may progress in kids without being identified.

Be very clear that there is no safe level of exposure to secondhand smoke in children. Health consequences can follow later in life despite healthy habits in adulthood. Still, choosing to engage in healthier lifestyles may help to delay or minimize the implications of your health destiny. We have yet to learn if long term healthy habits can negate childhood exposures.

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