Longer Reproductive Period Research Articles

The association between reproductive period and handgrip strength in postmenopausal women: a nationwide cross-sectional study.

Menarche and menopause are associated with muscle loss and strength in women. Handgrip strength (HGS) is a reliable measurement method of muscle strength. However, it is unclear whether the entire reproductive period, which encompasses both menarche and menopause, is associated with HGS in postmenopausal women. A total of 2,354 postmenopausal women aged 45-75 years were included for statistical analysis. The reproductive period was divided into tertiles, and HGS was divided into four quartiles. HGS was measured to evaluate muscle strength. Binary logistic regression analysis was used to identify significant predictors with the first quartile HGS, derived from quartile data. Multiple logistic regression analysis was used to assess the relationship between the reproductive period (exposure) and low HGS (outcome). We found that the more extended the reproductive period, the lower the risk of low absolute HGS. This trend persisted even after controlling for other variables. Specifically, the odds ratio for low absolute HGS was 0.752 (95% confidence interval [CI], 0.563-1.000) for the second tertile reproductive period and 0.683 (95% CI, 0.513-0.900) for the third tertile reproductive period, with the first tertile reproductive period as the reference. The odds ratio for low relative HGS was 0.761 (95% CI, 0.551-1.052) for the second tertile reproductive period and 0.732 (95% CI, 0.533-0.972) for the third tertile reproductive period, using first tertile reproductive period as the reference, after covariate adjustment. A longer reproductive period is associated with a decreased risk of low HGS in postmenopausal women.

Reproductive period duration and cognitive function in postmenopausal Latina women in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL).

A shorter reproductive period, a marker of estrogen exposure, has been related to cognitive impairment among older (>65years) non-Hispanic White women. We explored whether reproductive period duration, age at menarche, and age at menopause are related to cognitive function among postmenopausal Hispanic/Latina women. This cross-sectional analysis used baseline (Visit 1: 2008-2011) data from 3630 postmenopausal women in the Hispanic Community Health Study/Study of Latinos. Reproductive period duration, age at menarche, and age at menopause were assessed by self-report. Cognitive function variables included global cognition, verbal learning, memory, verbal fluency, and processing speed. Associations between each reproductive event and cognitive function were examined using multivariable linear and logistic regression analyses accounting for the complex survey design of the study and adjusting for socio-demographics, parity, and cardiovascular risk factors. We assessed whether associations differed by type of menopause (natural versus surgical) and hormone therapy use. The study population was on average aged 59years, with a mean reproductive period duration of 35years. Older age at menopause and a longer reproductive period were related to higher verbal learning (β=0.04, SE=0.02; p<0.05) and processing speed (ß=0.16, SE=0.04; p<0.001); associations were more pronounced for women with natural menopause. Older age at menarche was associated with lower scores on the digit symbol substitution test (ß=-0.62, SE=0.15; p<0.0001). There were no associations with global cognition. Among postmenopausal Hispanic/Latinas, a longer reproductive period was related to more favorable cognitive measures of verbal learning and processing speed. Our findings support the hypothesis that greater lifetime exposure to estrogens may be associated with higher cognitive performance.

Menstrual Factors, Reproductive History and Liver Cancer Risk: Findings from a Prospective Cohort Study in Chinese Women.

Many studies suggested that menstrual and reproductive factors affected the gender disparity in liver carcinogenesis, but the results were inconsistent. Moreover, there are few studies in Asian populations. Therefore, our study was to explore the association of menstrual and reproductive factors on liver cancer risk in Chinese women. 72,807 women were recruited in 1996 to 2000 and followed until the end of 2016 in Shanghai, China. Cox regression models were used to estimate HRs and 95% confidence intervals (CIs) for the association of menstrual and reproductive factors with liver cancer. 258 liver cancer cases were identified during 1,269,531 person-years of follow-up. In premenopausal and postmenopausal women, hormone replacement therapy (HRT) and injective contraceptives were positively associated with liver cancer risk respectively (HR, 1.23, 95% CI, 1.15-1.30; HR, 1.23, 95% CI, 1.17-1.30; HR, 1.07, 95% CI, 1.05-1.10; HR, 1.08, 95% CI, 1.05-1.11), while older age at menopause, longer reproductive period and fewer live births were associated with reduced risk, especially among postmenopausal women (Ptrend &lt; 0.05). In addition, liver cancer risk was elevated in postmenopausal women who received hysterectomy (HR, 1.07; 95% CI, 1.04-1.11), oophorectomy (HR, 1.05; 95% CI, 1.01-1.10) or oral contraceptives (HR, 1.06; 95% CI, 1.03-1.08). No association was found between age at menarche and liver cancer risk. Similar results were observed when excluding participants with less than 2 follow-up years. The findings suggested that female sex hormones could play significant roles in liver carcinogenesis. Our study was the first population-based cohort to provide epidemiology evidence of menstrual and reproductive factors on liver cancer risk in Chinese women.

Temperature dependent variations of life history traits of the land snail Allopeas gracile (Hutton, 1834) (Gastropoda: Subulinidae)

The ambient temperature of the environment influences the life history features of the land snails, thereby affecting the life history strategies. With the temperature being a reliable indicator of the seasonal changes, an attempt to explore the variations in the life history strategies of the pest snail Allopeas gracile (Hutton, 1834) (Gastropoda: Subulinidae) was carried out under four constant temperature grades - 15°C, 20°C, 30°C and 35°C (±1°C) temperatures throughout with laboratory temperature as controlled environment. The snail A. gracile was unable to complete their life cycle at 15°C and 20°C, without reaching reproductive maturity. In contrast, A. gracile maintained at laboratory temperatures (range 25–29 °C) exhibited long life span, longer reproductive period and longer generation time. However, the reproductive rate was highest at temperature 30°C. Perhaps, the warmer environment facilitated rapid growth, fast onset of reproduction with larger body size at early age. At a constant higher temperature of 35°C a state of inactivation was imposed when growth and reproduction became static. Apparently, the expression of the life history traits of A. gracile was supportive of an invasive nature, at a temperature ranging between 25°C and 35°C.

Female Reproductive Factors and the Risk of Bronchiectasis: A Nationwide Population-Based Longitudinal Study.

Although the oestrogen level is thought to be involved in the occurrence of bronchiectasis, limited data are available on the relationship between female reproductive factors and the risk of bronchiectasis. We performed a population-based retrospective cohort study of 959,523 premenopausal women and 1,362,401 postmenopausal women without a previous history of bronchiectasis who participated in a health screening exam in 2009 in South Korea. In premenopausal women, compared with a later age at menarche (≥16 years), an earlier menarche (<12 years) was associated with a reduced risk of bronchiectasis with an adjusted hazard ratio (aHR) (95% confidence interval (CI)) of 0.74 (0.67–0.81). However, there were no significant associations between other reproductive factors (breastfeeding, parity, or oral contraceptive use) and the risk of bronchiectasis. In postmenopausal women, the risk of bronchiectasis (aHR (95% CI)) was lower in those with an earlier menarche (0.79 (0.72–0.87) for <12 years vs. ≥16 years), a later menopause (0.90 (0.84–0.96) ≥55 years vs. <40 years), and a longer reproductive period (0.90 (0.86–0.94) for ≥40 years vs. <30 years). There was no significant relationship between parity and the risk of bronchiectasis. Although breastfeeding <1 year (aHR (95% CI) = 0.92 (0.87–0.97) for <0.5 years and 0.93 (0.88–0.97) for 0.5–1 years) and oral contraceptive use <1 year (0.97 (0.94–0.99)) reduced the risk of bronchiectasis, hormone replacement therapy ≥5 years increased the risk of bronchiectasis (1.24 (1.18–1.30)). Female reproductive factors are risk factors for developing bronchiectasis, showing a higher risk associated with shorter endogenous oestrogen exposure regardless of the menopausal status.

Duration of Reproductive Period and Risk of Transitioning to Mild Cognitive Impairment and Dementia

Decreasing estrogen levels have been hypothesized to be associated with increased risk of dementia, yet the current literature reveals conflicting results. This study aimed to determine whether a longer reproductive period, as an indicator of longer exposure to endogenous estrogens, is associated with risk of transitioning to MCI and dementia. Women 65 and over (N=1507) from the Rush Memory and Aging Project met eligibility for the current analysis. The average length of reproductive period (menopause age minus menarche age) was 35 years (range=16-68 years), and 64% had natural menopause. Multistate survival modeling (MSM) was used to estimate the influence of reproductive period on risk of transitioning through cognitive states including mild cognitive impairment (MCI) and clinically diagnosed dementia, as well as death. Multinomial regression models estimated total and cognitively unimpaired life expectancies based on the transition probabilities estimated by the MSM. Results suggest that women with more reproductive years were less likely to transition from no cognitive impairment (NCI) to MCI, and were more likely to return to NCI from MCI. Analyses also suggest two additional years free of cognitive impairment for women with 45 vs 25 years of reproduction, though reproduction period did not significantly impact overall life expectancy. This study suggests that the number of years of reproductive duration is not associated with the transition to dementia, but is possibly associated with delayed cognitive decline, reduced risk of MCI, increased likelihood of returning to NCI from MCI, and increased lifespan free of cognitive impairment.

Association of reproductive factors with dementia: A systematic review and dose-response meta-analyses of observational studies.

SummaryBackgroundAssociations between endogenous estrogen exposure indicators and risk of subtypes of dementia have been unclear.MethodsDatabases (PubMed, EMBASE and Web of Science) were searched electronically on 1st July and updated regularly until 12nd November 2021. Observational studies of English language were selected if reported an effect estimate [e.g., odds ratio (OR), rate ratio (RR) or hazard ratio (HR)] and 95% CI for the association between any exposure (age of menarche, age at menopause, reproductive period, estradiol level) and any endpoint variable [all-cause dementia, Alzheimer's disease (AD), vascular dementia (VD), cognitive impairment (CI)]. Random-effects models and dose-response meta-analyses were used to calculate estimates and to show the linear/nonlinear relationship. PROSPERO CRD42021274827.FindingsWe included 22 studies (475 9764 women) in this analysis. We found no clear relationship between late menarche (≥14 vs <14 years) and dementia, CI in categorical meta-analysis compared to a J-shape relationship in dose-response meta-analyses. Later menopause (≥45 vs <45 years) was consistently associated with a lower risk of all-cause dementia (pooled RR: 0.87, 95%CI: 0.78–0.97, I2=56.0%), AD (0.67, 0.44–0.99, I2=78.3%), VD (0.87, 0.80–0.94) and CI (0.82, 0.71–0.94, I2=19.3%) in categorical meta-analysis, showing similar results in dose-response meta-analyses. An inverse relationship between longer reproductive duration (≥35 vs <35 years) and dementia was observed in dose-response meta-analysis. In addition, estradiol levels after menopause were inversely correlated with the risk of AD and CI.InterpretationIn this study, later menopause and longer reproductive period were associated with a lower risk of dementia, while the relationship for menarchal age was J-shaped. There was an inverse relationship between higher postmenopausal estrogen levels and risk of AD and CI. Longitudinal study are needed to further explore the association between life-time estrogen exposure and risk of subtypes of dementia.FundingStart-up Foundation for Scientific Research in Shandong University.

Association of the Reproductive Period with Decreased Estimated Glomerular Filtration Rate in Menopausal Women: A Study from the Shanghai Suburban Adult Cohort and Biobank (2016-2020).

In previous studies, it has been documented that a short reproductive period is associated with a higher risk of diabetes, cardiovascular disease, and chronic kidney disease. This study aims to investigate the association of the reproductive period length with decreased renal function. This study obtained data from “the Shanghai Suburban Adult Cohort and Biobank”. An estimated glomerular filtration rate (eGFR) below 60 mL/min/1.73 m2 indicated decreased renal function during follow-up. Participants were grouped into quintiles by reproductive period. Logistic regression analysis was performed to examine the association between the reproductive period and decreased renal function. A total of 5503 menopausal women with baseline eGFR > 60 mL/min/1.73 m2 were included. Age, eGFR, and metabolic equivalent of task (MET) at baseline were 61.0 (range, 36.0–74.0) years, 92.2 (range, 60.1–194.5) mL/min/1.73 m2, and 1386 (range, 160–6678), respectively. A reproductive period of 37–45 years was associated with a lower risk of decreased eGFR (OR: 0.59, 95% CI: 0.35–1.00, p = 0.049) after adjusting for confounding variables. METs decreased the risk of decreased eGFR in women with a reproductive period of 37–45 years (OR: 0.43, 95% CI: 0.23–0.81, p = 0.010). Women with a longer reproductive period have a lower risk of decreased renal function. METs had an opposite influence on renal function in women with longer (decreased risk) or shorter (increased risk) reproductive periods.

Reproductive period and preclinical cerebrospinal fluid markers for Alzheimer disease: a 25-year study.

Objective:The aim of the study was to examine the association between reproductive period, as an indicator of endogenous estrogen, and levels of cerebrospinal fluid (CSF) biomarkers for Alzheimer disease (AD).Methods:A population-based sample of women from Gothenburg, Sweden was followed from 1968 to 1994 (N = 75). All women had natural menopause and were free from dementia. Information on reproductive period (age at menarche to age at menopause) was obtained from interviews from 1968 to 1980. Lumbar puncture was performed from 1992 to 1994 and CSF levels of Aβ42, Aβ40, P-tau, and T-tau were measured with immunochemical methods. Linear regression models adjusted for potential confounders were used to analyze the relationship between reproductive period and CSF biomarkers for AD.Results:Longer reproductive period was associated with lower levels of Aβ42 (β = −19.2, P = 0.01), higher levels of P-tau (β = 0.03, P = 0.01), and lower ratio of Aβ42/Aβ40 (β = −0.02, P = 0.01), while no association was observed for T-tau (β = 0.01, P = 0.46). In separate analyses, examining the different components of reproductive period, earlier age at menarche was associated higher levels of P-tau (β = −0.07, P = 0.031) and lower ratio of Aβ42/Aβ40 (β = 0.05, P = 0.021), whereas no association was observed with Aβ42 (β = 31.1, P = 0.11) and T-tau (β = −0.001, P = 0.98). Furthermore, no association was observed between age at menopause and CSF biomarkers for AD.Conclusions:Our findings suggest that longer exposure to endogenous estrogen may be associated with increased levels of AD biomarkers in the preclinical phase of AD. These findings, however, need to be confirmed in larger samples.Video Summary:.

The NAO affects the reproductive potential of small tuna migrating from the Mediterranean Sea

Several studies have confirmed that the North Atlantic Oscillation (NAO) has a direct effect on tuna across a range of biological aspects, such as abundance, catchability, recruitment, and physical condition (LC), especially during winter season (NAOw). However, its effect on reproductive biology has been barely investigated. Thus, the main aim of this study was to investigate the effect of the NAO on the physical condition index and gonadosomatic index (GSI) of the three most commercially exploited small species of migrating tuna (i.e. little tunny, bullet tuna, and Atlantic bonito) in the Mediterranean Sea. A positive direct correlation was found between little tunny and Atlantic bonito and the gonadosomatic and the physical condition indexes. In addition, a strong correlation was found between the NAOw and the gonadosomatic and LC indexes, which could lead to higher reproductive investment in gonad growth before the spawning season. In contrast, bullet tuna had a low LC index during peak gonad growth and were less affected by NAOw oscillations. In the case of bullet tuna, these results could be explained by a longer reproductive period that would lead to faster fat consumption before the reproductive period than in the other species considered and greater dependence on the surrounding environmental conditions for reproductive success.

Population dynamics of two troglobitic Troglorhopalurus (Scorpiones: Buthidae) scorpions from Brazil

Population dynamics studies raise relevant data to understanding ecological aspects and natural history of species as well as better conservation strategies. Using two scorpions species, Troglorhopalurus translucidus Lourenço, Baptista &amp;amp; Giupponi, 2004 and Troglorhopalurus lacrau (Lourenço &amp;amp; Pinto-da-Rocha, 1997) from Chapada Diamantina, Bahia state, Brazil, we estimate populacional parameters through mark and recapture methodology, and Jolly-Seber estimator. In addition, data on both species as sexual ratio, reproductive biology, growth, longevity, feeding habitats, and seasonality were analyzed in the caves and afterwards compared to other scorpion species as well as other arachnids. We captured and marked 82 specimens of T. translucidus and 65 specimens of T. lacrau. Population estimates were 361 ± 199 individuals to T. translucidus and 333 ± 252 to T. lacrau. Population estimates were considered high for the troglobitic scorpions when compared to subterranean arachnids or even with epigean species of scorpions. Both troglobitic scorpions featured remarkable differences in relation to epigean scorpions as higher longevity, longer reproductive period, slower growth. Besides T. translucidus showed marked seasonality with populational variations in rainy seasons in contrast to T. lacrau with populational stability. Suppl. material 1

Reproductive history and blood cell telomere length.

Telomeres are repetitive nucleotide sequences that protect against chromosomal shortening. They are replenished by telomerase, an enzyme that may be activated by estrogen. Women have longer telomeres than men; this difference might be due to estrogen exposure. We hypothesized that reproductive histories reflecting greater estrogen exposure will be associated with longer blood cell telomeres. Among women in the Sister Study (n= 1,048), we examined telomere length in relation to self-reported data on reproductive history. The difference between age at menarche and last menstrual period was used to approximate the reproductive period. Relative telomere length (rTL) was measured using qPCR. After adjustment, rTL decreased with longer reproductive period (β= -0.019, 95% CI: -0.04, -0.00, p= 0.03). Premenopausal women had shorter rTL than postmenopausal women (β= -0.051, 95% CI: -0.12, 0.01, p= 0.13). Longer breastfeeding duration was associated with longer rTL (β= 0.027, 95% CI: 0.01, 0.05, p=0.01); increasing parity was associated with shorter rTL (β = -0.016, 95% CI: -0.03, 0.00, p=0.07). Duration of exogenous hormone use was not associated with rTL. Reproductive histories reflecting greater endogenous estrogen exposure were associated with shorter rTL. Our findings suggest that longer telomeres in women are unlikely to be explained by greater estrogen exposure.

Effect of Reproductive History and Exogenous Hormone Use on Cognitive Function in Mid- and Late Life.

To investigate the association between reproductive history indicators of hormonal exposure, including reproductive period, pregnancy, and use of hormonal contraceptives, and mid- and late-life cognition in postmenopausal women. Analysis of baseline data from two randomized clinical trials: the Women's Isoflavone Soy Health and the Early vs Late Intervention Trial of Estradiol. University academic research center. Naturally menopausal women (N = 830). Participants were uniformly evaluated using a cognitive battery and a structured reproductive history questionnaire. Outcomes were composite scores for verbal episodic memory, executive function, and global cognition. Reproductive variables included ages at pregnancies, menarche, and menopause; reproductive period; number of pregnancies; and use of hormones for contraception and menopausal symptoms. Multivariable linear regression was used to evaluate associations between cognitive scores (dependent variable) and reproductive factors (independent variables), adjusting for age, race and ethnicity, income, and education. On multivariable modeling, age at menarche of 13 and older was inversely associated with global cognition (P = .05). Last pregnancy after age 35 was positively associated with verbal memory (P = .03). Use of hormonal contraceptives was positively associated with global cognition (P trend = .04), and verbal memory (P trend = .007). The association between hormonal contraceptive use and verbal memory and executive function was strongest for more than 10 years of use. Reproductive period was positively associated with global cognition (P = .04) and executive function (P = .04). In this sample of healthy postmenopausal women, reproductive life events related to sex hormones, including earlier age at menarche, later age at last pregnancy, longer reproductive period, and use of oral contraceptives are positively related to aspects of cognition in later life.

Association of Age at Menopause and Duration of Reproductive Period With Depression After Menopause: A Systematic Review and Meta-analysis.

Estrogens have neuroprotective and antidepressive effects; however, associations between indices of reduced endogenous estrogens and risk for postmenopausal depression have not been systematically explored. To investigate the association of age at menopause and the duration of the reproductive period with the risk for depression among postmenopausal women with naturally occurring menopause. A search strategy for use of MEDLINE was developed (through January 1, 2015) using the key terms menopause, climacteric, reproductive period, depression, and mood disorders. References of included studies and reviews were also screened; authors were contacted to maximize synthesized evidence. A total of 12,323 articles, without language restriction, were screened by pairs of reviewers to identify observational studies related to the study hypothesis; 14 studies were eligible for meta-analysis. Pairs of reviewers independently extracted information on study design and type of analysis by participants' characteristics and methods of depression ascertainment. Study quality was assessed using the Newcastle-Ottawa Scale, and fixed- or random-effects models were implemented. Pooled-effect estimates for depression, defined by psychiatric evaluation or validated instruments, by age at menopause and duration of the reproductive period. The 14 studies included in the meta-analysis represented 67,714 women. An inverse association (reported as odds ratio [OR]; 95% CI of 2-year increments) with depression in postmenopausal women was shown for increasing age at menopause (0.98; 0.96-0.99 [67,434 unique participants; 13 studies]) and duration of the reproductive period (0.98; 0.96-0.99 [54,715 unique participants; 5 studies]). Menopause at age 40 or more years compared with premature menopause was associated with a 50% decreased risk for depression (3033 unique participants; 4 studies). Pooling of studies examining severe depression showed a 5% decrease in risk of severe depression with increasing (2-year increment) age at menopause (52,736 unique participants; 3 studies); sensitivity analysis of studies controlling for past depression revealed similar results for age at menopause (0.98; 0.96-1.00 [48,894 unique participants; 3 studies). No heterogeneity or publication bias was evident in the main analyses. Longer exposure to endogenous estrogens, expressed as older age at menopause and longer reproductive period, is associated with a lower risk of depression in later life. Identifying women at higher risk for depression due to early menopause who could benefit from psychiatric intervention or estrogen-based therapies could be useful in the clinical setting.

Influence of some biological and social factors on aging rates and lifespan in women (on the example of studying Tiraspol long-livers)

This paper studies the influence of a number of biological (number of children, age of reaching menarche and climax, lifespan of parents) and social factors (place of living, nature of work) on aging rates in elderly and long-living women in Transnistria (city of Tiraspol). Biological age and aging rates are estimated using the “Diagnostics of Aging” computer program that includes a set of functional markers for the cardiovascular, respiratory, and neuromuscular systems and other data. Long-living women are characterized by later term of the first delivery and a longer reproductive period. As for social factors, the closest relation with aging rates and lifespan is noted for the character of professional activity: the women involved in work with a high physical load are characterized by accelerated aging rates.

Allocation patterns and phenology in wild and selected accessions of annual and perennial Physaria (Lesquerella, Brassicaceae)

Two processes that determine a good performance of plants in arid environments are phenology and resource allocation patterns. With a longer growing season and larger allocation to root, perennials achieve better access to resources and are more resilient to stresses than annuals. In traditional agricultural systems selection for optimal soil nutrient uptake has been a secondary breeding objective, because crops receive subsidies of water and fertilizers. However in arid lands, caution is required during domestication, to avoid changes in structural traits which may be the basis for sustainable production. Due to inherent differences in hierarchy among annual and perennial species, we propose that the changes in phenology and allocation brought about by selection will depend on the life cycle. We performed field studies comparing wild and selected accessions of annual and perennial species of Physaria. Life cycle determined the functional basis of seed yield. In annuals, selection resulted in early anthesis (1 week earlier), a lower allocation to roots and leaves (twofold lower), and an increase in harvest index (an increase of 62%). Selected perennials had higher biomass at maturity (45% higher), linked to a longer reproductive period (3 weeks longer) than their wild relatives. The vegetative allocation found in wild perennials remained unchanged after selection. While annuals selected for seed yield could compromise the capacity for acquisition of resources, selection in perennials did not modify the allocation strategy responsible for their positive adjustment to low resource environments. We found a trade off between seed yield potential and yield stability that resulted in lower performance of selected accessions in low quality environments in relation to their wild relatives.

Life long endogenous estrogen exposure and later adulthood cognitive function in a population of naturally postmenopausal women from Southern China: The Guangzhou Biobank Cohort Study

Estrogen has neurotrophic and neuroprotective properties in animal and in vitro studies. Epidemiological studies are inconclusive, but suggest a positive association between endogenous estrogen exposure (measured by reproductive period, the number of years between menarche and menopause) and later life cognitive function. Structural equation modeling was used in a cross-sectional study of 11,094 naturally postmenopausal multiparous Chinese older (≥50 years) women from the Guangzhou Biobank Cohort Study (phases 2 and 3) to assess the interrelationship of four proxies of higher endogenous estrogen exposure (longer reproductive period, older age of first pregnancy, lower parity and shorter average duration of breast feeding per child) with immediate and the delayed 10-word recall score in phases 2 and 3, and with the mini-mental state examination (MMSE) score in phase 3 (5641 women). Adjusted for age, education, childhood and adulthood socio-economic position and physical activity, longer reproductive period was associated with higher scores (0.02 words per year, 95% confidence interval (CI) 0.008-0.02 for delayed recall and 0.05 MMSE score, 95%CI 0.04-0.07, respectively). Lower parity and shorter average duration of breast-feeding per child were also associated with better cognitive function. In a large cohort of naturally postmenopausal Chinese women proxies of greater endogenous estrogen exposure were associated with better cognitive function. These findings support biological evidence for a cognitively protective role of endogenous estrogen.

Functional response and reproductive attributes of the aphidophagous ladybird beetle, Harmonia dimidiata (Fabricius) in oak trees of sericultural importance

Harmonia dimidiata (Fabricius) (Coleoptera: Coccinellidae) is the dominant predator of the aphid species Cervaphis quercus Takahashi. This aphid is a serious pest of oak trees in several parts of north-east India. Young leaves of oak trees are used in sericulture by rural people and by industry in several parts of north-east India. The effect of different aphid densities on food consumption and fecundity of H. dimidiata was studied in the laboratory. Female beetles were maintained from the time of eclosion till death at a fixed density of 25, 50, 75,100 or 125 aphids. Both the functional response and the reproductive numerical response showed the upper asymptote at 100 adult aphids/female. At this density, females matured earlier and produced more eggs over a longer reproductive period. At lower prey densities, females matured late and they either did not produce eggs or produced fewer eggs. At the higher prey densities, females did not produce more eggs than the asymptote. Results suggested that H. dimidiata are an effective predator of C. quercus aphids on oak trees and could be exploited as a biological control agent in the rising phase of aphid population growth.

Life-time estrogen exposure and cognitive functioning in later life

While recent studies suggest that exogenous estrogen treatment could help reduce age-related cognitive decline and delay the onset of dementia, this has not been found consistently. Few studies have considered the influence of life-time estrogen exposure which may have an independent effect on cognition and/or modulate treatment response. The aim of this study was to examine whether factors related to estrogen exposure across the life-time were associated with cognitive function in postmenopausal women. A battery of cognitive tests were administered at baseline and at 2 and 4 years of follow-up to evaluate cognitive performance among a population-based cohort of 996 French women aged 65 years or older, who were recruited as part of the ESPRIT study. Detailed reproductive histories were also obtained. Logistic regression models, controlling for an extensive range of potential confounding factors, were generated to determine whether hormone-related factors across a woman's lifetime were associated with poor cognitive performance in later life. Age at first menses was negatively associated with performance on the tasks of visual memory and psychomotor speed, while a longer reproductive period was associated with better verbal fluency. Likewise, women who had their first child at a young age performed significantly worse on each of these tasks, as well as on a measure of global cognitive function. The results also suggest that current hormone therapy may be beneficial for a number of cognitive domains, however, in multivariate analysis, women performed significantly better on the task of visual memory only. In contrast, in analysis adjusted for baseline cognitive performance and a range of other factors, none of the reproductive variables were associated with a decline in cognitive performance or the incidence of dementia during the 4-year follow-up period. In addition to hormone therapy, certain hormone-related events across the lifetime are also associated with cognitive functioning in later life. They were not observed in this study to modulate dementia risk; however, this should be verified over a longer follow-up period. Further studies will also be required to determine whether lifetime hormonal exposure may modify women's response to hormone therapy after the menopause.

Reproductive period and risk of dementia in postmenopausal women.

Exogenous estrogen use may lower risk of dementia in postmenopausal women. A relationship between long-term exposure to endogenous estrogens and incident dementia has been hypothesized but not studied. To determine whether a longer reproductive period, as an indicator of longer exposure to endogenous estrogens, is associated with lower risk of dementia and Alzheimer disease (AD) in women who have natural menopause. The Rotterdam Study, a population-based prospective cohort study conducted in the Netherlands. A total of 3601 women aged 55 years or older who did not have dementia at baseline (1990-1993) and had information on age at menarche, age at menopause, and type of menopause. Participants were reexamined in 1993-1994 and 1997-1999 and were continuously monitored for development of dementia. Incidence of dementia, based on Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition criteria, and AD, based on National Institute of Neurological Disorders and Stroke/Alzheimer's Disease and Related Disorders Association criteria, compared by quartiles of reproductive period among women with natural menopause. During 21 046 person-years of follow-up (median follow-up, 6.3 years), 199 women developed dementia, including 159 who developed AD. After adjusting for age, dementia was not clearly associated with length of reproductive period. However, after adjusting for multiple covariates, women with natural menopause and more reproductive years had an increased risk of dementia (adjusted rate ratio [RR] for women with >39 reproductive years [highest quartile] compared with <34 reproductive years [lowest quartile], 1.78; 95% confidence interval [CI], 1.12-2.84). The adjusted RR per year of increase was 1.04 (95% CI, 1.01-1.08). For risk of AD, the adjusted RRs were 1.51 (95% CI, 0.91-2.50) and 1.03 (95% CI, 1.00-1.07), respectively. Risk of dementia associated with a longer reproductive period was most pronounced in APOE epsilon4 carriers (adjusted RR for >39 reproductive years compared with <34 reproductive years, 4.20 [95% CI, 1.97-8.92] for dementia and 3.42 [95% CI, 1.51-7.75] for AD), whereas in noncarriers, no clear association with dementia or AD was observed. Our findings do not support the hypothesis that a longer reproductive period reduces risk of dementia in women who have natural menopause.