A new study from Tasmania, Australia and Finland, published in the European Heart Journal, used sensitive ultrasound measurements to quantify carotid artery thickening and narrowing among almost 5,000 adults, and related the results to the degree of childhood exposure to parental smoke (i.e., second-hand smoke, SHS).
The researchers were led by Dr. Seana Gall of the University of Tasmania, and her team included scientists from the University of Turku, Finland. The study subjects included 1,375 Australians, aged 9-15 years at baseline (1985) who underwent carotid artery ultrasound evaluation 20 years later, at ages ranging from 26-36. The Finnish subjects were enrolled in 1980, and were between the ages of 3-18 years at that time. The final study group numbered 2,041. Parental smoking was determined simply as either none, or one or both parents were smokers. The authors controlled for known confounders, mainly current or recent study subject smoking as well as other cardiovascular risk factors.
The results were quantitated as a well-described parameter known as carotid intima-media thickness (CIMT), which measures degree of narrowing of the carotid artery by fatty deposits, a reflection of generalized atherosclerosis. After accounting for factors as described confounders the CIMT among patients whose parents were both smokers was significantly greater than those patients whose parents did not smoke. The absolute difference was tiny: 0.015 mm, but the difference was highly significant, statistically.
"Exposure to passive smoke in childhood causes direct and irreversible damage to the structure of the arteries," Dr. Gall told Kate Kelland of Reuters. She said parents, or even those thinking about becoming parents, should quit smoking - both to aid their own health and protect the future health of their children. According to the study s authors, having both parents smoke was associated with a vascular age 3.3 years greater at follow-up than having neither parent smoke. The effect was independent of participant smoking at baseline and follow-up and other confounders and was uniform across categories of age, sex, adult smoking status, and cohort.
ACSH s Dr. Gil Ross had this perspective: While neither 0.015 mm nor 3.3 years might seem of major import, especially given the lack of actual outcome data, the essence of this study remains unalterable: parents should not expose their children to smoke, SHS or passive smoke or whatever it s called. The acute effects are bad enough: exacerbation of upper respiratory and ear infections, and asthma. SHS s contribution to chronic diseases is less clear, but this study should be a springboard to actual outcome studies of long-term effects of childhood SHS exposure. A recent large study supported earlier studies which failed to show a link to lung cancer from SHS, but that doesn t exonerate it.
This study lends further credence to the data contained in our groundbreaking 1998 publication, "The Irreversible Health Effects of Cigarette Smoking."