The relationship between smoki…
The relationship between smoking and early menopause is debatable and unclear specially the dose and duration effect have no clearly demarcated evidence.
To solve the unclarity, this study is conducted. Researchers believed that large sample size with long duration and subgroup analysis is required. A 206,256 follow up study was conducted with in 20 years. Women who were premenopausal in 1989 at the time of enrollment were included in this study. Totally 2754 participants experienced early natural menopause. Two-fold of risk was experienced by those who were current smoking against those who never smoked. The risk is increased with dose response among current smokers and duration increasing.
Only heavy former smokers had slight risk while light smokers of their equivalent had no risk compared to never smokers. However, the risk level of past smokers cannot regain the never smoker status. In a study conducted on mice the morphology and quantity of egg production was compromised compared to the control group. By then the production of ova ceased early before the average time. If the effect of cigarette on mice had impairment on mice ovary which has congruent finding with this study[early menopause] (6) the increased dose effect and its impact on the function of ovary is one indication of menopause eventually cessation of fertilization will appear. Cognizant of the minimal risk identified among former and current light smokers, it is difficult to conclude the risk level is minimal that can lead people to have smoking of the minimal dose. Because smoking has other health impacts.
The risk identified in this study corresponds with other studies. Two systematic reviews had similar report with the current study on the relationship between current smoking and early menopause. Researchers have felt that there is lack of evidence on the level of risk and dose of cigarette consumed. A finding from New Zealand supports the finding of this study showing that risk increases with increased dose. Women who reported smoking 20 or more cigarette per day at baseline and at the 14 years of follow up and current smokers were at 50% more risk compared to never smoked women. In this study increased dose in former and current smoker brought risk while moderate dose and never smoked status has no different effect. A 21 years cohort study revealed that cigarette smoking facilitates early menopause while smoking cessation interventions were associated with late age of menopause.
(7) The risk level was also different between quitters before and after 30s. Despite women quit smoking before 30s, their risk level wouldn’t return to the never smoked risk level. Conversely, those who proceed smoking smokers quitted before 30s had lesser risk compared to those who quitted at 40s. A study from Korea also affirmed this finding with the evidence of 0.75-year lower rate of early menopause among smokers compared to nonsmokers. The risk is more with increased dose when the initiation of smoking gets lower.(8) As it has been seen in animal models, cigarette has multiple effect on ovarian follicles.
It affects the biochemical and structure of the ovary which finally causes lowered estrogen and increased luteinizing hormone. The risk in this study has increased with increased dose and duration which would have increased its effect on the ovarian follicles. A study conducted using women reproductive survey data showed that lower luteal phase progesterone metabolite level which influences the function of ovary intern affects the release of pituitary hormones. Eventually, reproductive problems like infertility and early menopause could happen.(9) Smoking status stratified with BMI categories has not difference. Censored groups because of oophorectomy/hysterectomy hadn’t association with smoking history. This study had an explicit identification of confounders and effect estimators.
For instance, the result without body mass index and the general analysis had no difference. The effect of smoking on early menopause is unequivocally similar throughout the categories of body mass index classes. Knowing the fact that, this cohort study had large sample size followed for about 20 years, there are limitations observed. Self-reported smoking and menopause status were taken without triangulation because of conducting laboratory test is costwise inefficient. Self-reporting was found effective in many researches regarding smoking habit. But in the baseline assessment past smokers have been asked to recall their history retrospectively which may cause recall bias. ConclusionThis study substantiates the evidence of dose effect of cigarette smoking risk to early natural menopause.
Women who consumed minimal dose or quit smoking at their early reproductive age had slight to no effect. Thus, reducing cigarette consumption and cessation of smoking are important public health interventions that could spare women from early menopause and sooner or later other consequences related smoking can be averted. Despite of the shred of evidence reported, still the evidence found is not that much stronger. This study has been conducted for long time but controlling the other effects is hard to achieve. Other studies which should be finished with in lab like on laboratory animals could come up with the impact of dose change. Otherwise the argument will continue. On the other hand, data was collected biennially which is hard for participants to remind their trend of smoking.
Educational interventions and rehabilitation of exiting from the habit of smoking can be establishing to promote smokers to cease smoking and prevent the potential but nonsmoker.