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Menstrual Disruption with Exercise Is Not Linked to an Energy Availability Threshold.

ABSTRACT: INTRODUCTION:Chronic reductions in energy availability (EA) suppress reproductive function. A particular calculation of EA quantifies the dietary energy remaining after exercise for all physiological functions. Reductions in luteinizing hormone pulse frequency have been demonstrated when EA using this calculation is <30 kcal·kg·fat-free mass (ffm)·d. PURPOSE:We determined whether menstrual disturbances (MD) are induced when EA is <30 kcal·kg ffm·d. METHODS:Thirty-five sedentary, ovulatory women age 18 to 24 yr (weight, 59.0 ± 0.8 kg; body mass index, 21.8 ± 0.4 kg·m) completed a diet and exercise intervention over three menstrual cycles. Participants were randomized to groups that varied in the magnitude of negative energy balance created by the combination of exercise and energy restriction. Menstrual disturbances were determined using daily urinary estrone-1-glucuronide and pregnanediol glucuronide, midcycle luteinizing hormone, and menstrual calendars. In a secondary analysis, we calculated EA from energy balance data and tested the association of EA with MD. RESULTS:A generalized linear mixed-effects model showed that the likelihood of a MD decreased by 9% for each unit increase in EA (odds ratio, 0.91; 95% confidence interval, 0.84-0.98; P = 0.010). No specific value of EA emerged as a threshold below which MD were induced. When participants were partitioned into EA tertile groups (low EA, 23.4-34.1; n = 11; moderate EA, 34.9-40.7; n = 12, and high EA, 41.2-50.1; n = 12 [kcal·kg ffm·d]), estrone-1-glucuronide (P < 0.001), pregnanediol glucuronide (P < 0.001), and luteal phase length (P = 0.031) decreased significantly, independent of tertile. CONCLUSIONS:These findings do not support that a threshold of EA exists below which MD are induced but do suggest that MD increase linearly as EA decreases. Menstrual disturbances can likely be prevented by monitoring EA using a simplified assessment of metabolic status.

SUBMITTER: Lieberman JL

PROVIDER: S-EPMC5820163 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature

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Menstrual Disruption with Exercise Is Not Linked to an Energy Availability Threshold.

Lieberman Jay L JL DE Souza Mary Jane MJ Wagstaff David A DA Williams Nancy I NI

Medicine and science in sports and exercise 20180301 3

<h4>Introduction</h4>Chronic reductions in energy availability (EA) suppress reproductive function. A particular calculation of EA quantifies the dietary energy remaining after exercise for all physiological functions. Reductions in luteinizing hormone pulse frequency have been demonstrated when EA using this calculation is <30 kcal·kg·fat-free mass (ffm)·d.<h4>Purpose</h4>We determined whether menstrual disturbances (MD) are induced when EA is <30 kcal·kg ffm·d.<h4>Methods</h4>Thirty-five seden ...[more]

PMID: 29023359

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Project description:BackgroundGirls and women need effective, safe, and affordable menstrual products. Single-use products are regularly selected by agencies for resource-poor settings; the menstrual cup is a less known alternative. We reviewed international studies on menstrual cup leakage, acceptability, and safety and explored menstrual cup availability to inform programmes.MethodsIn this systematic review and meta-analysis, we searched PubMed, Cochrane Library, Web of Science, Popline, Cinahl, Global Health database, Emerald, Google Scholar, Science.gov, and WorldWideScience from database inception to May 14, 2019, for quantitative or qualitative studies published in English on experiences and leakage associated with menstrual cups, and adverse event reports. We also screened the Manufacturer and User Facility Device Experience database from the US Food and Drug Administration for events related to menstrual cups. To be eligible for inclusion, the material needed to have information on leakage, acceptability, or safety of menstrual cups. The main outcome of interest was menstrual blood leakage when using a menstrual cup. Safety outcomes of interest included serious adverse events; vaginal abrasions and effects on vaginal microflora; effects on the reproductive, digestive, or urinary tract; and safety in poor sanitary conditions. Findings were tabulated or combined by use of forest plots (random-effects meta-analysis). We also did preliminary estimates on costs and environmental savings potentially associated with cups. This systematic review is registered on PROSPERO, number CRD42016047845.FindingsOf 436 records identified, 43 studies were eligible for analysis (3319 participants). Most studies reported on vaginal cups (27 [63%] vaginal cups, five [12%] cervical cups, and 11 [25%] mixed types of cups or unknown) and 15 were from low-income and middle-income countries. 22 studies were included in qualitative or quantitative syntheses, of which only three were of moderate-to-high quality. Four studies made a direct comparison between menstrual cups and usual products for the main outcome of leakage and reported leakage was similar or lower for menstrual cups than for disposable pads or tampons (n=293). In all qualitative studies, the adoption of the menstrual cup required a familiarisation phase over several menstrual cycles and peer support improved uptake (two studies in developing countries). In 13 studies, 73% (pooled estimate: n=1144; 95% CI 59-84, I2=96%) of participants wished to continue use of the menstrual cup at study completion. Use of the menstrual cup showed no adverse effects on the vaginal flora (four studies, 507 women). We identified five women who reported severe pain or vaginal wounds, six reports of allergies or rashes, nine of urinary tract complaints (three with hydronephrosis), and five of toxic shock syndrome after use of the menstrual cup. Dislodgement of an intrauterine device was reported in 13 women who used the menstrual cup (eight in case reports, and five in one study) between 1 week and 13 months of insertion of the intrauterine device. Professional assistance to aid removal of menstrual cup was reported among 47 cervical cup users and two vaginal cup users. We identified 199 brands of menstrual cup, and availability in 99 countries with prices ranging US$0·72-46·72 (median $23·3, 145 brands).InterpretationOur review indicates that menstrual cups are a safe option for menstruation management and are being used internationally. Good quality studies in this field are needed. Further studies are needed on cost-effectiveness and environmental effect comparing different menstrual products.FundingUK Medical Research Council, Department for International Development, and Wellcome Trust.

Project description:Transient hypothyroxinaemia of prematurity (THOP) presents as decreased free thyroxine without an increase in thyroid stimulating hormone. Thyroxine availability is important in case of premature birth, and THOP could be associated with impaired adaptation to extra-uterine life but the association of thyroxine level and clinical status has not yet been clearly defined. Aim: To defined a free thyroxine threshold likely associated with neonatal clinical impairment and outcomes at age three years. Methods: This retrospective cohort study included infants born before or at 28 weeks' gestation at the Regional Maternity in Nancy, France. We defined a free thyroxine threshold as a function of clinical impairment by Receiver Operating Curve analysis, validated by log likelihood iteration in binary logistic regression, in infants born from October 2008 to December 2012 and meeting neonatal clinical impairment criteria. This threshold was validated in a distinct cohort of infants born from January 2014 to December 2016. Clinical impairment was defined as assisted ventilation requirement at seven days of age plus four minor clinical disorders among heart rate, blood pressure, temperature, serum sodium and potassium, APGAR score at five minutes, vasopressor treatment and patent ductus arteriosus. The first cohort was assessed at age three years for neurodevelopmental outcomes. Results: We identified a ≤10 pmol/L threshold with 85.7% sensitivity and 51% specificity. From the first and second cohorts, 196 and 176 infants respectively had available data, and 85% (97/112) and 26% (20/78) with free thyroxine ≤10 pmol/L met clinical impairment criteria. For infants with values >10 pmol/L, 41% (35/84) and 3% (3/98) from the first and second cohorts met impairment criteria. Of 147 children with available data at age 3 years, 65% (58/89) with neonatal free thyroxine ≤10 pmol/L had adverse neurodevelopmental outcomes vs. 34% (20/58) with >10 pmol/L (OR 3.55; 95% confidence interval, 1.77-7.13; p < 0.001). Conclusion: A free thyroxine level ≤10 pmol/L in infants is associated with neonatal clinical impairment and poor outcome at age three years.

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Menstrual Disruption with Exercise Is Not Linked to an Energy Availability Threshold.

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Menstrual Disruption with Exercise Is Not Linked to an Energy Availability Threshold.

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