Research

Nicotine binding to receptor linked to breast cancer cell growth
A new study published in the Journal of the National Cancer Institute indicates that nicotine binding to nicotinic acetylcholine receptors (nAchR), which are known to support nicotine addiction, may also promote breast cancer development. Researchers examined 276 breast tumor samples to determine whether nicotine interacted with nAchR to promote the growth of tumor cells. They found that cancerous cells expressed the alpha 9 subunit (α9-nAchR) at 7.84 times the level of normal cells, with higher levels of expression in advanced cases of cancer compared to earlier stages of cancer. Further experiments showed that reducing the levels of α9-nAchR inhibited tumor growth, while increasing levels of α9-nAchR or treating normal breast cells with nicotine promoted cancer development. The results give a better understanding of a mechanism through which nicotine may contribute to breast cancer development. Click here to read more about the study, or read the study abstract.

Chronic musculoskeletal pain and cigarette smoking among a representative sample of Canadian adolescents and adults
A recent study shows that people with chronic back pain were more likely to smoke than those without chronic pain. Data from the 2007-2008 Canadian Community Health Survey (CCHS) were used to gather data on chronic back pain and arthritis as well as smoking status of Canadian citizens aged twelve and older. Controlling for sociodemographic factors and history of mood or anxiety disorders, those with chronic back pain were 41% more likely and those with arthritis were 34% more likely to smoke cigarettes daily than those without either condition. Because of the cross-sectional study design, it is not possible to prove causation, and the investigators note that more research needs to be done to address smoking and chronic pain. Click here to read the abstract of the study, available in the November 2010 issue of Addictive Behavior.

Association of adolescent symptoms of depression and anxiety with daily smoking and nicotine dependence in young adulthood: Findings from a 10-year longitudinal study
A study published in the current issue of Addiction indicates that adolescent smokers with symptoms of depression and anxiety may be more likely to be dependent on nicotine as young adults than adolescents without such symptoms. A cohort of 1,943 adolescents was assessed at regular intervals during their teens and twice more in young adulthood for depression and anxiety, tobacco use, and nicotine dependence. The results showed that adolescents with depression and anxiety symptoms who smoked less than daily or daily were 3.3 and 1.9 times more likely, respectively, to report nicotine dependence in young adulthood than those who had low levels of these symptoms as adolescents. This implies that smokers with depression and anxiety symptoms are at increased risk of nicotine dependence later in life, and primary care providers should promote smoking prevention and cessation among their young patients with depression and anxiety. Click here to read the study abstract.

Smoking mothers link to infertility
A new study has found that the number of immature reproductive cells was significantly reduced in male embryos from mothers who smoke, indicating that smoking during pregnancy may have a negative effect on male children’s fertility. In order to compare differences between smokers and nonsmokers in the number of germ cells, the cells that later develop into sperm in males or eggs in females, in their offspring, researchers examined the testes of 24 legally aborted male embryos. They found that germ cells were reduced by 55% in embryos exposed to maternal smoking compared to those that were not exposed; similarly, non-reproductive somatic cells were reduced by 37% in embryos exposed to tobacco smoke. The effects were dose-dependent, with fewer germ cells found in embryos from heavy smokers than lighter smokers. This study replicated similar findings from previous research on female embryos. The effects of the decreased amount of germ cells in embryos exposed to maternal tobacco smoke could potentially have consequences related to future fertility. Read more here, or read the abstract of the study, published in Human Reproduction.

Birth weight and adult hypercholesterolemia: subgroups of small-for-gestational-age based on maternal smoking status during pregnancy
A new study published in Epidemiology indicates that babies that were exposed to tobacco smoke in the womb and born small for gestational age (SGA) are at significantly higher risk for hypercholesterolemia (high cholesterol) than SGA babies that were not exposed. A total of 1,625 participants in the Collaborative Perinatal Project were followed as adults for an average of 39 years. Recorded fetal growth, maternal smoking status during pregnancy, and clinical diagnosis of high cholesterol were obtained for the study. The results indicate that, compared to normal-sized infants, SGA subgroups exposed to heavy smoking in utero were at 2.5 times higher risk of hypercholesterolemia. The results demonstrate that the known association between being born SGA and developing hypercholesterolemia later in life may be limited to certain subgroups of SGA infants. Future research is necessary to explain the biologic mechanisms behind these results. Click here to read the abstract of the study.

'Snus' tobacco linked to stillbirth risk
New research shows that maternal use of snus is associated with an increased risk of stillbirth compared to non-users of tobacco. In order to determine the effects of snus usage on pregnancy complications, data were analyzed from the Swedish Medical Birth Register on demographic information, reproductive history, snus and cigarette use status, and details on pregnancy complications from nearly 611,000 women who were pregnant between 1999 and 2006. Data analysis showed that women who used snus while pregnant were at 60% higher risk of suffering a stillbirth than non-users of tobacco. By comparison, light smokers (1-9 cigarettes per day) faced a 40% increase in risk and heavy smokers (10 or more cigarettes per day) were at 2.4 times the risk of stillbirths compared to non-users of tobacco. Although the mechanism behind the increased stillbirth risk is not clear, the results suggest that using snus is not a safe alternative to smoking, and should be avoided by pregnant women to reduce the risk of pregnancy complications. Read more here, or read the abstract of the study, published in Epidemiology.

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