15,659 research outputs found
An acute bout of cycling does not induce compensatory responses in pre-menopausal women not using hormonal contraceptives
There is a clear need to improve understanding of the effects of physical activity and exercise on appetite control. Therefore, the acute and short-term effects (three days) of a single bout of cycling on energy intake and energy expenditure were examined in women not using hormonal contraceptives. Sixteen active (n = 8) and inactive (n = 8) healthy pre-menopausal women completed a randomised crossover design study with two conditions (exercise and control). The exercise day involved cycling for 1 h (50% of maximum oxygen uptake) and resting for 2 h, whilst the control day comprised 3 h of rest. On each experimental day participants arrived at the laboratory fasted, consumed a standardised breakfast and an ad libitum pasta lunch. Food diaries and combined heart rate-accelerometer monitors were used to assess free-living food intake and energy expenditure, respectively, over the subsequent three days. There were no main effects or condition (exercise vs control) by group (active vs inactive) interaction for absolute energy intake (P > 0.05) at the ad libitum laboratory lunch meal, but there was a condition effect for relative energy intake (P = 0.004, ηp2 = 0.46) that was lower in the exercise condition (1417 ± 926 kJ vs. 2120 ± 923 kJ). Furthermore, post-breakfast satiety was higher in the active than in the inactive group (P = 0.005, ηp2 = 0.44). There were no main effects or interactions (P > 0.05) for mean daily energy intake, but both active and inactive groups consumed less energy from protein (14 ± 3% vs. 16 ± 4%, P = 0.016, ηp2 = 0.37) and more from carbohydrate (53 ± 5% vs. 49 ± 7%, P = 0.031, ηp2 = 0.31) following the exercise condition. This study suggests that an acute bout of cycling does not induce compensatory responses in active and inactive women not using hormonal contraceptives, while the stronger satiety response to the standardised breakfast meal in active individuals adds to the growing literature that physical activity helps improve the sensitivity of short-term appetite control
Sex differences in the associations between birthweight and lipid levels in middle-age: findings from the 1958 British birth cohort
Objective
To examine sex differences in birthweight–lipid associations.
Methods and results
Using prospectively collected data on birthweight and non-fasting lipid levels at age 44–45 y from the 1958 British birth cohort (3603 men and 3583 women), sex differences in birthweight–lipid associations were examined.
There were inverse associations between birthweight and total and low-density-lipoprotein (LDL)-cholesterol among women (a 1 kg increase in birthweight was associated with a 0.13 mmol/L reduction in total cholesterol (p < 0.001) and a 0.07 mmol/L reduction in LDL-cholesterol (p = 0.02)) but no associations among men (p = 0.005 and p = 0.01, respectively, for birthweight × sex interactions). There was an inverse association between birthweight and triglycerides of a similar magnitude in both sexes (a 1 kg increase in birthweight was associated with a 7% reduction in triglyceride levels in sex-adjusted models (p < 0.001)). There was no association between birthweight and high-density-lipoprotein-cholesterol. Associations were largely unaltered after adjustment for covariates. Of birthweight, current height and BMI, the latter was the strongest predictor of lipid levels.
Conclusions
The finding of an inverse association between birthweight and triglycerides in both sexes and of inverse associations between birthweight and total and LDL-cholesterol only in women suggests that the mechanisms underlying the associations with birthweight may vary for different lipids
Estimation of Dietary Iron Bioavailability from Food Iron Intake and Iron Status
Currently there are no satisfactory methods for estimating dietary iron absorption (bioavailability) at a population level, but this is essential for deriving dietary reference values using the factorial approach. The aim of this work was to develop a novel approach for estimating dietary iron absorption using a population sample from a sub-section of the UK National Diet and Nutrition Survey (NDNS). Data were analyzed in 873 subjects from the 2000–2001 adult cohort of the NDNS, for whom both dietary intake data and hematological measures (hemoglobin and serum ferritin (SF) concentrations) were available. There were 495 men aged 19–64 y (mean age 42.7±12.1 y) and 378 pre-menopausal women (mean age 35.7±8.2 y). Individual dietary iron requirements were estimated using the Institute of Medicine calculations. A full probability approach was then applied to estimate the prevalence of dietary intakes that were insufficient to meet the needs of the men and women separately, based on their estimated daily iron intake and a series of absorption values ranging from 1–40%. The prevalence of SF concentrations below selected cut-off values (indicating that absorption was not high enough to maintain iron stores) was derived from individual SF concentrations. An estimate of dietary iron absorption required to maintain specified SF values was then calculated by matching the observed prevalence of insufficiency with the prevalence predicted for the series of absorption estimates. Mean daily dietary iron intakes were 13.5 mg for men and 9.8 mg for women. Mean calculated dietary absorption was 8% in men (50th percentile for SF 85 µg/L) and 17% in women (50th percentile for SF 38 µg/L). At a ferritin level of 45 µg/L estimated absorption was similar in men (14%) and women (13%). This new method can be used to calculate dietary iron absorption at a population level using data describing total iron intake and SF concentration
Multiple imputations to study the association between childhood growth and early breast cancer
Is there an independent effect of polycystic ovary syndrome (PCOS) and menopause on the prevalence of subclinical atherosclerosis in middle aged women?
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Elevated plasma ceramide levels in post-menopausal women: a cross-sectional study.
Circulating ceramide levels are abnormally elevated in age-dependent pathologies such as cardiovascular diseases, obesity and Alzheimer's disease. Nevertheless, the potential impact of age on plasma ceramide levels has not yet been systematically examined. In the present study, we quantified a focused panel of plasma ceramides and dihydroceramides in a cohort of 164 subjects (84 women) 19 to 80 years of age. After adjusting for potential confounders, multivariable linear regression analysis revealed a positive association between age and ceramide (d18:1/24:0) (β (SE) = 5.67 (2.38); p = .0198) and ceramide (d18:1/24:1) (β (SE) = 2.88 (.61); p < .0001) in women, and between age and ceramide (d18:1/24:1) in men (β (SE) = 1.86 (.77); p = .0179). In women of all ages, but not men, plasma ceramide (d18:1/24:1) was negatively correlated with plasma estradiol (r = -0.294; p = .007). Finally, in vitro experiments in human cancer cells expressing estrogen receptors showed that incubation with estradiol (10 nM, 24 h) significantly decreased ceramide accumulation. Together, the results suggest that aging is associated with an increase in circulating ceramide levels, which in post-menopausal women is at least partially associated with lower estradiol levels
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Menopausal Status Dependence of the Timing of Breast Cancer Recurrence after Surgical Removal of the Primary Tumour
Introduction: Information on the metastasis process in breast cancer patients undergoing primary tumour removal may be extracted from an analysis of the timing of clinical recurrence. Methods: The hazard rate for local-regional and/or distant recurrence as the first event during the first 4 years after surgery was studied in 1173 patients undergoing mastectomy alone as primary treatment for operable breast cancer. Subset analyses were performed according to tumour size, axillary nodal status and menopausal status. Results: A sharp two-peaked hazard function was observed for node-positive pre-menopausal patients, whereas results from node-positive post-menopausal women always displayed a single broad peak. The first narrow peak among pre-menopausal women showed a very steep rise to a maximum about 8–10 months after mastectomy. The second peak was considerably broader, reaching its maximum at 28–30 months. Post-menopausal patients displayed a wide, nearly symmetrical peak with maximum risk at about 18–20 months. Peaks displayed increasing height with increasing axillary lymph node involvement. No multi-peaked pattern was evident for either pre-menopausal or post-menopausal node-negative patients; however, this finding should be considered cautiously because of the limited number of events. Tumour size influenced recurrence risk but not its timing. Findings resulting from the different subsets of patients were remarkably coherent and each observed peak maintained the same position on the time axis in all analysed subsets. Conclusions: The risk of early recurrence for node positive patients is dependent on menopausal status. The amount of axillary nodal involvement and the tumour size modulate the risk value at any given time. For pre-menopausal node-positive patients, the abrupt increase of the first narrow peak of the recurrence risk suggests a triggering event that synchronises early risk. We suggest that this event is the surgical removal of the primary tumour. The later, broader, more symmetrical risk peaks indicate that some features of the corresponding metastatic development may present stochastic traits. A metastasis development model incorporating tumour dormancy in specific micro-metastatic phases, stochastic transitions between them and sudden acceleration of the metastatic process by surgery can explain these risk dynamics
Critical appraisal of CRP measurement for the prediction of coronary heart disease events: new data and systematic review of 31 prospective cohorts.
BACKGROUND: Non-uniform reporting of relevant relationships and metrics hampers critical appraisal of the clinical utility of C-reactive protein (CRP) measurement for prediction of later coronary events. METHODS: We evaluated the predictive performance of CRP in the Northwick Park Heart Study (NPHS-II) and the Edinburgh Artery Study (EAS) comparing discrimination by area under the ROC curve (AUC), calibration and reclassification. We set the findings in the context of a systematic review of published studies comparing different available and imputed measures of prediction. Risk estimates per-quantile of CRP were pooled using a random effects model to infer the shape of the CRP-coronary event relationship. RESULTS: NPHS-II and EAS (3441 individuals, 309 coronary events): CRP alone provided modest discrimination for coronary heart disease (AUC 0.61 and 0.62 in NPHS-II and EAS, respectively) and only modest improvement in the discrimination of a Framingham-based risk score (FRS) (increment in AUC 0.04 and -0.01, respectively). Risk models based on FRS alone and FRS + CRP were both well calibrated and the net reclassification improvement (NRI) was 8.5% in NPHS-II and 8.8% in EAS with four risk categories, falling to 4.9% and 3.0% for 10-year coronary disease risk threshold of 15%. Systematic review (31 prospective studies 84 063 individuals, 11 252 coronary events): pooled inferred values for the AUC for CRP alone were 0.59 (0.57, 0.61), 0.59 (0.57, 0.61) and 0.57 (0.54, 0.61) for studies of 10 years follow up, respectively. Evidence from 13 studies (7201 cases) indicated that CRP did not consistently improve performance of the Framingham risk score when assessed by discrimination, with AUC increments in the range 0-0.15. Evidence from six studies (2430 cases) showed that CRP provided statistically significant but quantitatively small improvement in calibration of models based on established risk factors in some but not all studies. The wide overlap of CRP values among people who later suffered events and those who did not appeared to be explained by the consistently log-normal distribution of CRP and a graded continuous increment in coronary risk across the whole range of values without a threshold, such that a large proportion of events occurred among the many individuals with near average levels of CRP. CONCLUSIONS: CRP does not perform better than the Framingham risk equation for discrimination. The improvement in risk stratification or reclassification from addition of CRP to models based on established risk factors is small and inconsistent. Guidance on the clinical use of CRP measurement in the prediction of coronary events may require updating in light of this large comparative analysis
Comparison of anogenital distance and correlation with vulvo-vaginal atrophy: a pilot study on premenopausal and postmenopausal women
OBJECTIVES:
Anogenital distance (AGD) represents the space between labia posterior commissure and anus. This was pilot study to investigate how menopause and so lack of oestrogens affects AGD.
METHODS:
A total of 109 patients were enrolled. AGD was measured in lithotomy position using sterile paper ruler. Anogenital index (AGI) was used to control 2 variables of height and weight (body mass index, kg/m2). Vaginal health index (VHI) was used to evaluate vaginal wellness. Female sexual function index (FSFI) questionnaire was administered to all women to evaluate the impact of menopause on their sexual function.
RESULTS:
AGD (30.87 ± 2.98 vs. 17.57 ± 2.18; P = 0.0001) and AGI (1.40 ± 0.21 vs. 0.70 ± 0.15; P = 0.0001) were both significantly lower in the postmenopausal group. Postmenopausal women were affected by vulvovaginal atrophy (VVA) significantly. Thus, VHI scores were dramatically worse in postmenopausal group (23.95 ± 1.28 vs. 10.75 ± 3.41; P = 0.0001) as well as FSFI results (32.68 ± 2.25 vs. 19.78 ± 5.46; P = 0.0001).
CONCLUSIONS:
This study confirms that AGD in post-menopausal women was significantly shorter than AGD in premenopausal women, correlating with an increase of VVA and sexual impairment. Changes of AGD and AGI demonstrated to predict hormonal changes that may occur after menopause
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