Early age at first sexual intercourse and early pregnancy are risk factors for cervical cancer in developing countries.
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ABSTRACT:
SUBMITTER: Louie KS
PROVIDER: S-EPMC2670004 | biostudies-other | 2009 Apr
REPOSITORIES: biostudies-other
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Project description:ObjectiveIn this study, we aimed to investigate whether age first had sexual intercourse (AFSI) and lifetime number of sexual partners (LNSP) have a direct causal effect on cervical cancer by Mendelian randomization (MR) analysis.MethodsFour approaches were used for MR Analysis, including MR-Egger, weighted method, weighted median, and inverse variance weighted (IVW). MR Pleiotropy RESidual Sum and Outlier (MR-PRESSO) as well as MR-Egger regression analysis were conducted to detect whether there was pleiotropy between IVs and outcome, and the outlier SNPs can be detected by MR-PRESSO. The presence or absence of heterogeneity among IVs was suggested according to Cochran's Q statistic. Leave-one-out sensitivity analysis was performed to identify and remove SNPs which could independently change the results. We corrected the results using Bonferroni correction.ResultsFrom the results of IVW, AFSI had a negative effect on cervical cancer (OR = 0.996, 95 % CI: 0.995, 0.998 P = 1.70E-07), which still persisted after Bonferroni correction. However, no causal effect of LNSP on cervical cancer was found according to the IVW results (OR = 1.003, 95 % CI: 1.000, 1.007, P = 0.071). From the results of MR-PRESSO and MR-Egger, no SNP with horizontal pleiotropy between cervical cancer was detected and no SNP was identified as an outlier SNP. Cochran's Q statistic suggested that no heterogeneity existed among IVs of AFSI and LNSP. According to Leave-one-out analysis, the results of MR did not change after excluding any single IV.ConclusionThis MR study reveals that early AFSI has a causal effect on cervical cancer.
| S-EPMC10788439 | biostudies-literature
Project description:Young age at first sexual intercourse (AFI) is an important risk factor for cervical cancer, but no simple statistical model of its influence has been established. We investigated the relationship between risk of cervical carcinoma and time since first intercourse using data on monogamous women (5,074 cases and 16,137 controls) from the International Collaboration of Epidemiological Studies of Cervical Cancer. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated from pooled data on 20 studies using conditional logistic regression. The OR for invasive cervical carcinoma is approximately proportional to the square of time since first intercourse (exponent 1.95, 95% CI: 1.76-2.15) up to age 45. First cervical infection with human papillomavirus (HPV) often occurs soon after first sexual intercourse, so early AFI is a reasonable proxy for early age at first exposure to HPV. In addition, age-specific incidence rates of cervical cancer in unscreened populations remain fairly constant above age 45. Cervical cancer thus resembles other cancers caused by strong early-stage carcinogens, with incidence rates proportional to a power of time since first exposure and also resembles cancers of the breast and other hormone-dependent epithelia, where a similar flattening of age-specific incidence rates is seen at the time menopausal changes start. Taken together, these observations suggest that HPV vaccination may prevent the majority of cervical cancers by delaying HPV infection without necessarily providing lifetime protection against HPV.
| S-EPMC3982220 | biostudies-literature
Project description:BackgroundThere is increasing evidence that sex hormones are involved in the development of lung cancer, but the correlation between the reproductive behavior that changes sex hormone levels and lung cancer is not yet clear. Many previous studies have investigated the association between reproductive factors and lung cancer risk, but the results have been inconsistent. Therefore, we conducted a two-sample Mendelian randomization (MR) analysis to explore the potential relationship between age at first sexual intercourse (AFS), age at menarche, and age at menopause, and lung cancer.MethodsWe performed a MR analysis of the data from the genome-wide association study (GWAS) of European ancestry to evaluate the independent effects of three reproductive behaviors on lung cancer overall (LUCA), lung adenocarcinoma (LUAD), lung squamous cell carcinoma (LUSC), and small cell lung cancer (SCLC). We mainly used the inverse-variance weighting method for the MR analysis. Sensitivity was determined by a MR-pleiotropy residual sum and outlier analysis, a weighted median analysis, a MR-Egger analysis, and a leave-one-out analysis.ResultsThe MR analysis results revealed that older AFS had a causal relationship with LUCA [odds ratio (OR) =0.6283, 95% confidence interval (CI): 0.4959-0.7961, P=0.0001), LUAD (OR =0.7042, 95% CI: 0.4967-0.9984, P=0.049), and LUSC (OR =0.6231, 95% CI: 0.4386-0.8853, P=0.0083).ConclusionsOur results revealed a causal relationship between older AFS and a lower risk of lung cancer. Our findings emphasize the importance of providing sex education, as early sexual intercourse may have undesirable effects. In addition, early psychological treatment is also essential.
| S-EPMC11304150 | biostudies-literature
Project description:The timing of first sexual intercourse is often defined in terms of chronological age, with particular focus on "early" first sex. Arguments can be made for a more nuanced concept of readiness and appropriateness of timing of first intercourse. Using data from the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3), conducted in 2010-2012, this study examined whether a context-based measure of first intercourse-termed sexual competence-was associated with subsequent sexual health in a population-based sample of 17-to 24-year-olds residing in Britain (n = 2,784). Participants were classified as "sexually competent" at first intercourse if they reported the following four criteria: contraceptive protection, autonomy of decision (not due to external influences), that both partners were "equally willing," and that it happened at the "right time." A lack of sexual competence at first intercourse was independently associated with testing positive for human papillomavirus (HPV) at interview; low sexual function in the past year; and among women only, reported sexually transmitted infection (STI) diagnosis ever; unplanned pregnancy in the past year; and having ever experienced nonvolitional sex. These findings provide empirical support for defining the nature of first intercourse with reference to contextual aspects of the experience, as opposed to a sole focus on chronological age at occurrence.
| S-EPMC5214675 | biostudies-literature
Project description:PurposeWe examined timing of first voluntary sexual intercourse as a joint function of parental separation during childhood and parental history of alcoholism.MethodsData were drawn from a birth cohort of female like-sex twins (n = 569 African ancestry [AA]; n = 3,415 European or other ancestry [EA]). Cox proportional hazards regression was conducted predicting age at first sex from dummy variables coding for parental separation and parental alcoholism. Propensity score analysis was also employed to compare intact and separated families, stratified by predicted probability of separation.ResultsEarlier sex was reported by EA twins from separated and alcoholic families, compared to EA twins from intact nonalcoholic families, with effects most pronounced through the age of 14 years. Among AA twins, effects of parental separation and parental alcoholism were largely nonsignificant. Results of propensity score analyses confirmed unique risks from parental separation in EA families, where consistent effects of parental separation were observed across predicted probability of separation. For AA families, there was poor matching on risk factors presumed to predate separation, which limited interpretability of survival-analytic findings.ConclusionsIn European American families, parental separation during childhood is an important predictor of early-onset sex, beyond parental alcoholism and other correlated risk factors. To characterize risk for African Americans associated with parental separation, additional research is needed where matching on confounders can be achieved.
| S-EPMC4409650 | biostudies-literature
Project description:There is substantial variation in the timing of significant reproductive life events such as menarche and first sexual intercourse. Life history theory explains this variation as an adaptive response to an individual's environment and it is important to examine how traits within life history strategies affect each other. Here we applied Mendelian randomization (MR) methods to investigate whether there is a causal effect of variation in age at menarche and age at first sexual intercourse (markers or results of exposure to early life adversity) on outcomes related to reproduction, education and risky behaviour in UK Biobank (N = 114 883-181 255). Our results suggest that earlier age at menarche affects some traits that characterize life history strategies including earlier age at first and last birth, decreased educational attainment, and decreased age at leaving education (for example, we found evidence for a 0.26 year decrease in age at first birth per year decrease in age at menarche, 95% confidence interval: -0.34 to -0.17; p < 0.001). We find no clear evidence of effects of age at menarche on other outcomes, such as risk taking behaviour. Age at first sexual intercourse was also related to many life history outcomes, although there was evidence of horizontal pleiotropy which violates an assumption of MR and we therefore cannot infer causality from this analysis. Taken together, these results highlight how MR can be applied to test predictions of life history theory and to better understand determinants of health and social behaviour.
| S-EPMC7295202 | biostudies-literature
Project description:ObjectivesTo assess the prospective associations of physical activity behaviors and screen time with early sexual intercourse initiation (i.e., before 15 years) in a large sample of adolescents.MethodsWe used two waves of data from the Rotterdam Youth Monitor, a longitudinal study conducted in the Netherlands. The analysis sample consisted of 2,141 adolescents aged 12 to 14 years (mean age at baseline = 12.2 years, SD = 0.43). Physical activity (e.g., sports outside school), screen time (e.g., computer use), and early sexual intercourse initiation were assessed by means of self-report questionnaires. Logistic regression models were tested to assess the associations of physical activity behaviors and screen time (separately and simultaneously) with early sexual intercourse initiation, controlling for confounders (i.e., socio-demographics and substance use). Interaction effects with gender were tested to assess whether these associations differed significantly between boys and girls.ResultsThe only physical activity behavior that was a significant predictor of early sexual intercourse initiation was sports club membership. Adolescent boys and girls who were members of a sports club) were more likely to have had early sex (OR = 2.17; 95% CI = 1.33, 3.56. Significant gender interaction effects indicated that boys who watched TV ≥2 hours/day (OR = 2.00; 95% CI = 1.08, 3.68) and girls who used the computer ≥2 hours/day (OR = 3.92; 95% CI = 1.76, 8.69) were also significantly more likely to have engaged in early sex.ConclusionThese findings have implications for professionals in general pediatric healthcare, sexual health educators, policy makers, and parents, who should be aware of these possible prospective links between sports club membership, TV watching (for boys), and computer use (for girls), and early sexual intercourse initiation. However, continued research on determinants of adolescents' early sexual initiation is needed to further contribute to the strategies for improving adolescents' healthy sexual development and behaviors.
| S-EPMC4981454 | biostudies-literature
Project description:Background: Low contraceptive use among women in Niger is one of main causes of early childbearing and unwanted pregnancies, which affect maternal and child health. Education and place of residence have been cited as factors affecting modern contraceptive use. Methods: We investigated the separate and joint effects of the place of residence and education on the time to modern contraceptive uptake among women aged 15-24 in Niger. The study used data from the second round of the 2016 Niger Performance Monitoring and Accountability 2020 (PMA2020) project. Survival analysis was applied for 830 women. Results: Nelson-Aalen curves show that urban women had higher hazards of (and shorter delays in) modern contraceptive uptake as compared to their rural counterparts. Also, the higher the level of education, the higher the hazards of (and the shorter the delays in) modern contraceptive uptake. Findings from the multivariate (survival) analysis confirms these figures and provides the net effect of the place of residence on modern contraceptive uptake. Whether living in urban or rural areas of Niger, what matters more is the level of education. Conclusions: Family planning programmes concerning adolescent and young women should focus more on women with no education and those that are illiterate.
| S-EPMC6795034 | biostudies-literature
Project description:Reproductive behavior characteristics may be influenced by both social and individual factors. Recent studies have revealed that personality traits might be related to reproductive characteristics in adulthood. Little is known about potential mediators or moderators of relations between personality and reproductive behavior. The present study examines the relation between personality traits measured in early adolescence and the number of children people have by age 27, with an attempt to identify moderation and mediation effects. We used data from the longitudinal cohort (N = 585) collected as a part of the Child Development Project. Personality was measured with the use of Lanthier's Big Five Personality Questionnaire. Results from regression analyses and structural equation models showed that four of the five personality traits (except extraversion) were related to the number of children individuals had by age 27, and these associations were mediated by the age of first intercourse and participants' familial and educational plans. We also identified moderation effects of IQ and SES both on the associations of personality traits with mediators and the number of children by age 27.
| S-EPMC7362713 | biostudies-literature
Project description:BackgroundEarly sexual intercourse (SI) may have long-lasting negative impacts on health-related quality of life (HRQoL). So far, these impacts have been studied using age for defining early SI instead of feelings about its timing. The present study examined the association between feelings about the timing of first SI and current HRQoL.MethodsData came from the 2014 cross-sectional Health Behaviour in School-aged Children (HBSC) study in French-speaking Belgium. Among participants aged 16-20?years who already had SI, 1778 were included in analyses. Univariate and multivariate logistic regressions were performed, including potential confounders.ResultsOne quarter of adolescents (26.4%) had poor HRQoL, 19.8% expressed a negative feeling about the timing of first SI and 19.6% did not think about it. Compared with adolescents who thought first SI happened at the right time or wished it had happened sooner, adolescents who had a negative feeling about the timing and those who did not think about it were more likely to have a poor HRQoL (cOR?=?1.67 (1.28-2.17) and cOR?=?1.37 (1.05-1.80), respectively). After adjustment, associations were no more significant (aOR?=?1.22 (0.91-1.63) and aOR?=?1.22 (0.91-1.64)). Sex disparity in expressing a negative feeling mostly explained the difference between crude and adjusted analyses.ConclusionFurther research is needed to better understand such a complex relationship. The high proportion of adolescents having poor HRQoL and negative feeling about the timing of first SI shows how important it is to find out effective prevention for both domains.
| S-EPMC6466645 | biostudies-literature