Modeling the relation of smoking to the ovarian function
Creators: name: University Of California Office Of The President
Publisher: name: University of California Office of the President
publisherIdentifier: https://ror.org/00dmfq477
publisherIdentifierScheme: ROR
Year: 2024

description: Other than its well-known carcinogenic effect, tobacco smoke might also act as a toxin to the reproductive endocrine environment in women. Menstruation and ovarian steroid patterns are primary markers of human female reproductive endocrinologic and ovarian function. Researches only involve laboratory animals or a few women have show that tobacco smoke could influence ovarian sex hormone biosythesis. Investigation of menstruation and its hormonal bases based on large-sample-size data is limited. In fact, major difficulties in analysis and interpretation of cyclic menstrual and hormone data arise when much of the observed variability in menstrual characteristics stems from changes within women as opposed to differences between women and steroid data are curved over an entire menstrual cycle.
 
 
 
 
 
 The improvement of less-cost biological assay techniques, rapid development of computer hardware/software and considerable exploration of modern statistical inference methods allow us to model human ovarian function based on cycle-to-cycle daily diary and urine collection now. The primary goal of the research proposed is to explore methodology for investigating the influence of cigarette smoking in the presence of other host and environmental factors on the ovarian function of women based on daily diary and urinary assay data. The study data were collected previously. The importance of this existing database is that it contains information on urine specimens collected not only over an entire menstrual cycle for each of 402 women but also over several successive cycles for most of those women. The effects of cigarette smoking on ovarian steroid secretion and metabolic clearance rate (MCR) of progesterone, in premenopausal women will be assessed with control of variables we collected, such as age, race, parity, body mass index (BMI), alcohol use, caffeine consumption and physical activity. We also want to evaluate the relation of menstrual cycle length and follicular and luteal phase lengths with tobacco exposure.
 
 
 
 
 
 The response variables from an individual are usually correlated since they were measured repeatedly over time. In the present proposed study, appropriate models that allow for such correlation is discussed. Menstrual characteristics will be modeled as linear functions of the smoking and other variables using the general linear mixed model (GLMM). But typical menstrual cycle measures may not be sensitive indicators of changes or disturbances in hormonal function resulting from cigarette smoke exposure. We will model curves which reflect hormone profiles over time using variants of the GLMM, which are expected to be more sensitive to such changes. The above analyses rely on the assumption of normality of the data and on having moderate to large sample sizes. We will perform a special technique, bootstrap analysis, in order to check on these assumptions and to provide inferences that are less dependent on these assumptions.
 
 
 
 
 
 The present proposed study should shed light on the mechanisms by which cigarette smoke adversely affects women's endocrinologic and menstrual function and provide new approaches for scientists in their efforts to detect more sensitively the tobacco-related health effects with respect to reproduction in premenopausal women.