Sleep disorders and risk of infertility: A meta-analysis of observational studies.
PloS one
OBJECTIVE:The purpose of this study was to determine the relationship between sleep disorders and risk of infertility. METHOD:Three databases (PubMed, Embase, and Cochrane Library) were searched form their inception to April 30, 2023. Information of study design, control group and experimental group, number of participants, and study outcomes was extracted. The quality of the studies was evaluated using the Newcastle-Ottawa Scale (NOS scale) and the Agency for Healthcare Research and Quality (AHRQ scale). Narrative synthesis and meta-analysis were used to analyze these studies. RESULT:Eight cohort, cross-sectional, and case-control studies were considered. The reviewed studies were high-quality. Pooled analysis showed that the risk of infertility was 1.43-fold higher in patients with sleep disturbance (HR = 1.43, 95% CI, 0.97-2.11, z = 1.79), but this was not statistically different; the risk was 1.58-fold higher in patients with OSA compared to those without OSA (HR = 1.58, 95%, CI, 0.99-2.52, z = 1.91), but this was not statistically significant. Wake-up time is also associated with infertility (OR = 1.14; 95%CI = 1.01-1.28; P = 0.037). For every hour they stay awake beyond 8:00 AM, participants had a 41% higher risk of infertility (P = 0.004). The early-to-bed/late-to-rise (EL), LE, and LL groups had a higher risk of infertility than the EE group. CONCLUSION:The present study did not find an association between sleep disorders and the risk of infertility. Therefore, more observational studies are warranted to explore the association between sleep disorders and the risk of infertility.
10.1371/journal.pone.0293559
Sleep Deficiency: Epidemiology and Effects.
Clinics in chest medicine
Adequate sleep is an important pillar of physical and mental health. Sleep deficiency, resulting from short sleep or suboptimal sleep quality, is highly prevalent in modern society. Occupation, social demands, psychiatric disorders, physical disorders, and sleep disorders are some of the contributing factors to sleep deficiency. Some populations are at increased risk of sleep deficiency based on ethnicity, age, marital status, sex, and hospitalization. Sleep deficiency influences cognition, alertness, mood, behavior, diabetes, cardiovascular health, renal function, immune system, and respiratory physiology. This review summarizes the epidemiology and effects of sleep deficiency.
10.1016/j.ccm.2022.02.001
Telomeres, oxidative stress, and timing for spontaneous term and preterm labor.
American journal of obstetrics and gynecology
Telomeres are nucleoprotein complexes located at the distal ends of chromosomes. In adults, progressive telomere shortening occurs throughout the lifetime and is thought to contribute to progressive aging, physiological senescence, multiorgan dysfunction, and ultimately, death. As discussed in this review, multiple lines of evidence provide support for the biological plausibility that a telomere-based clock mechanism also determines the length of gestation, leading to the onset of labor (parturition). After telomere expansion at the beginning of pregnancy, the telomere lengths in the gestational tissues (ie, the placenta and fetal membranes) progressively shorten throughout the remainder of pregnancy. The rate of telomere shortening can be accelerated by conditions that affect the mother and result in oxidative stress. Preterm births in the United States are associated with multiple risk factors that are linked with increased oxidative stress. Antioxidant vitamins (ie, vitamins E and C) mitigate the effects of oxidative stress and delay or prevent telomere shortening. Clinical trials with vitamins E and C and with multivitamins started during the periconception period have been associated with reduced rates of preterm births. In the United States, African-American women have a 2-3-fold higher rate of preterm birth. African-American women have multiple risk factors for premature birth, all of which are distinct and potentially additive with regard to epigenetic telomere shortening. The "weathering effect" is the hypothesis to explain the increased rates of chronic illness, disabilities, and early death observed in African-Americans. With regard to pregnancy, accelerated weathering with the associated telomere shortening in the gestational tissues would not only explain the preterm birth disparity but could also explain why highly educated, affluent African-American women continue to have an increased rate of preterm birth. These studies suggest that the racial disparities in preterm birth are potentially mediated by telomere shortening produced by lifetime or even generational exposure to the effects of systemic racism and socioeconomic marginalization. In conclusion, this review presents multiple lines of evidence supporting a novel hypothesis regarding the biological clock mechanism that determines the length of pregnancy, and it opens the possibility of new approaches to prevent or reduce the rate of spontaneous preterm birth.
10.1016/j.ajog.2022.04.024
Accelerated epigenetic clock aging in maternal peripheral blood and preterm birth.
American journal of obstetrics and gynecology
BACKGROUND:Epigenetic clocks use CpG DNA methylation to estimate biological age. Acceleration is associated with cancer, heart disease, and shorter life span. Few studies evaluate DNA methylation age and pregnancy outcomes. AgeAccelGrim is a novel epigenetic clock that combines 7 DNA methylation components. OBJECTIVE:This study aimed to determine whether maternal biological aging (via AgeAccelGrim) is associated with early preterm birth. STUDY DESIGN:A prospective cohort of patients with singleton pregnancies and at high risk of spontaneous preterm birth delivering at a tertiary university hospital were included in this study. Genome-wide CpG methylation was measured using the Illumina EPIC BeadChip (Illumina, Inc, San Diego, CA) from maternal blood samples obtained at <28 weeks of gestation. AgeAccelGrim and its 7 DNA methylation components were estimated by the Horvath DNA methylation age online tool. Positive values are associated with accelerated biological aging, whereas negative values are associated with slower biological aging relative to each subject's age. The primary outcome was preterm birth at <34 weeks of gestation (any indication). The secondary outcomes were preterm birth at <37 and <28 weeks of gestation. AgeAccelGrim was analyzed as a continuous variable and in quartiles. Exploratory analyses evaluated each of the 7 DNA methylation components included in the composite AgeAccelGrim. Data were analyzed by chi-square test, t test, rank-sum test, logistic regression (controlling a priori for maternal age, cell counts, low socioeconomic status, and gestational age at the time of sample collection), and Kaplan-Meier survival analyses. The log-rank test was used to test the equality of the survival functions. RESULTS:Overall, 163 patients met the inclusion criteria. Of the patients, 48%, 39%, and 21% delivered at <37, <34, and <28 weeks of gestation, respectively. The median AgeAccelGrim was -0.35 years (interquartile range, -2.24 to 1.31) for those delivering at term. Those delivering preterm had higher AgeAccelGrim values that were inversely proportional to delivery gestational age (preterm birth at <37 weeks of gestation: +0.40 years [interquartile range: -1.21 to +2.28]; preterm birth at <34 weeks of gestation: +0.51 years [interquartile range: -1.05 to +2.67]; preterm birth at <28 weeks of gestation: +1.05 years [interquartile range: -0.72 to +2.72]). Estimated DNA methylation of the 7 epigenetic clock component values was increased among those with preterm birth at <34 weeks of gestation, although the differences were only significant for DNA methylation of plasminogen activation inhibitor 1. In regression models, AgeAcccelGrim was associated with an elevated risk of preterm birth with increasing magnitude for increasing severity of preterm birth. For each 1-year increase in the AgeAccelGrim value (ie, each 1-year increase in biological age compared with chronologic age), the adjusted odds of preterm birth were 11% (adjusted odds ratio, 1.11; 95% confidence interval, 1.00-1.24), 13% (adjusted odds ratio, 1.13; 95% confidence interval, 1.01-1.26), and 18% (adjusted odds ratio, 1.18; 95% confidence interval, 1.04-1.35) higher for preterm birth at <37, <34, and <28 weeks of gestation, respectively. Similarly, individuals with accelerated biological aging (≥75th percentile AgeAccelGrim) had more than double the odds of preterm birth at <34 weeks of gestation (adjusted odds ratio, 2.36; 95% confidence interval, 1.10-5.08) and more than triple the odds of preterm birth at <28 weeks of gestation (adjusted odds ratio, 3.89; 95% confidence interval, 1.61-9.38). The adjusted odds ratio for preterm birth at <37 weeks of gestation was 1.73 but spanned the null (adjusted odds ratio, 1.73; 95% confidence interval, 0.81-3.69). In Kaplan-Meier survival analyses, those in the highest AgeAccelGrim quartile delivered the earliest (log-rank P value of <.001). CONCLUSION:Accelerated biological aging was associated with preterm birth among high-risk patients. Future research confirming these findings and elucidating factors that slow biological aging may improve birth outcomes.
10.1016/j.ajog.2023.09.003