Title: Modelling the impact of birth control policies on China’s population and age: effects of delayed births and minimum birth age constraints
We consider age-structured models with an imposed refractory period between births. These models can be used to formulate alternative population control strategies to China’s one-child policy. By allowing any number of births, but with an imposed delay between births, we show how the total population can be decreased and how a relatively older age distribution can be generated. This delay represents a more ‘continuous’ form of population management for which the strict one-child policy is a limiting case. Such a policy approach could be more easily accepted by society. Our analyses provide an initial framework for studying demographics and how social constraints influence population structure. more »« less
Leahy, John; Thapar, Aditi
(, American economic journal Macroeconomics)
Gilchrist, Simon
(Ed.)
We exploit cross-sectional variation in the response of US states to an identified monetary policy shock to study how the impact of monetary policy varies with the age structure of the population. We find that the economy’s response is weaker the greater the share of population under 35 years of age and stronger the greater the share between 40 and 65. We find that all age groups become more responsive to monetary policy shocks when the proportion of the middle-aged increases. We provide evidence consistent with middle-aged entrepreneurs starting and expanding businesses in response to an expansionary monetary shock. (JEL E23, E24, E32, E43, E52, J11, R23)
Bozack, Anne K.; Rifas-Shiman, Sheryl L.; Gold, Diane R.; Laubach, Zachary M.; Perng, Wei; Hivert, Marie-France; Cardenas, Andres
(, Clinical Epigenetics)
Abstract BackgroundEpigenetic age acceleration (EAA) and epigenetic gestational age acceleration (EGAA) are biomarkers of physiological development and may be affected by the perinatal environment. The aim of this study was to evaluate performance of epigenetic clocks and to identify biological and sociodemographic correlates of EGAA and EAA at birth and in childhood. In the Project Viva pre-birth cohort, DNA methylation was measured in nucleated cells in cord blood (leukocytes and nucleated red blood cells, N = 485) and leukocytes in early (N = 120, median age = 3.2 years) and mid-childhood (N = 460, median age = 7.7 years). We calculated epigenetic gestational age (EGA; Bohlin and Knight clocks) and epigenetic age (EA; Horvath and skin & blood clocks), and respective measures of EGAA and EAA. We evaluated the performance of clocks relative to chronological age using correlations and median absolute error. We tested for associations of maternal-child characteristics with EGAA and EAA using mutually adjusted linear models controlling for estimated cell type proportions. We also tested associations of Horvath EA at birth with childhood EAA. ResultsBohlin EGA was strongly correlated with chronological gestational age (Bohlin EGAr = 0.82,p < 0.001). Horvath and skin & blood EA were weakly correlated with gestational age, but moderately correlated with chronological age in childhood (r = 0.45–0.65). Maternal smoking during pregnancy was associated with higher skin & blood EAA at birth [B(95% CI) = 1.17 weeks (− 0.09, 2.42)] and in early childhood [0.34 years (0.03, 0.64)]. Female newborns and children had lower Bohlin EGAA [− 0.17 weeks (− 0.30, − 0.04)] and Horvath EAA at birth [B(95% CI) = − 2.88 weeks (− 4.41, − 1.35)] and in childhood [early childhood: − 0.3 years (− 0.60, 0.01); mid-childhood: − 0.48 years (− 0.77, − 0.18)] than males. When comparing self-reported Asian, Black, Hispanic, and more than one race or other racial/ethnic groups to White, we identified significant differences in EGAA and EAA at birth and in mid-childhood, but associations varied across clocks. Horvath EA at birth was positively associated with childhood Horvath and skin & blood EAA. ConclusionsMaternal smoking during pregnancy and child sex were associated with EGAA and EAA at multiple timepoints. Further research may provide insight into the relationship between perinatal factors, pediatric epigenetic aging, and health and development across the lifespan.
Chersich, Matthew Francis; Pham, Minh Duc; Areal, Ashtyn; Haghighi, Marjan Mosalam; Manyuchi, Albert; Swift, Callum P; Wernecke, Bianca; Robinson, Matthew; Hetem, Robyn; Boeckmann, Melanie; et al
(, BMJ)
Abstract Objective To assess whether exposure to high temperatures in pregnancy is associated with increased risk for preterm birth, low birth weight, and stillbirth. Design Systematic review and random effects meta-analysis. Data sources Medline and Web of Science searched up to September 2018, updated in August 2019. Eligibility criteria for selecting studies Clinical studies on associations between high environmental temperatures, and preterm birth, birth weight, and stillbirths. Results 14 880 records and 175 full text articles were screened. 70 studies were included, set in 27 countries, seven of which were countries with low or middle income. In 40 of 47 studies, preterm births were more common at higher than lower temperatures. Exposures were classified as heatwaves, 1°C increments, and temperature threshold cutoff points. In random effects meta-analysis, odds of a preterm birth rose 1.05-fold (95% confidence interval 1.03 to 1.07) per 1°C increase in temperature and 1.16-fold (1.10 to 1.23) during heatwaves. Higher temperature was associated with reduced birth weight in 18 of 28 studies, with considerable statistical heterogeneity. Eight studies on stillbirths all showed associations between temperature and stillbirth, with stillbirths increasing 1.05-fold (1.01 to 1.08) per 1°C rise in temperature. Associations between temperature and outcomes were largest among women in lower socioeconomic groups and at age extremes. The multiple temperature metrics and lag analyses limited comparison between studies and settings. Conclusions Although summary effect sizes are relatively small, heat exposures are common and the outcomes are important determinants of population health. Linkages between socioeconomic status and study outcomes suggest that risks might be largest in low and middle income countries. Temperature rises with global warming could have major implications for child health. Systematic review registration PROSPERO CRD 42019140136 and CRD 42018118113.
Yao, Guidan; Bedewy, Ahmed M.; Shroff, Ness B.
(, Mobihoc)
null
(Ed.)
In this paper, we consider a status update system, in which update packets are sent to the destination via a wireless medium that allows for multiple rates, where a higher rate also naturally corresponds to a higher error probability. The data freshness is measured using age of information, which is defined as the age of the recent update at the destination. A packet that is transmitted with a higher rate, will encounter a shorter delay and a higher error probability. Thus, the choice of the transmission rate affects the age at the destination. In this paper, we design a low-complexity scheduler that selects between two different transmission rate and error probability pairs to be used at each transmission epoch. This problem can be cast as a Markov Decision Process. We show that there exists a threshold-type policy that is age-optimal. More importantly, we show that the objective function is quasi-convex or non-decreasing in the threshold, based on the system parameters values. This enables us to devise a low-complexity algorithm to minimize the age. These results reveal an interesting phenomenon: While choosing the rate with minimum mean delay is delay-optimal, this does not necessarily minimize the age.
Basso, Olga; Willis, Sydney K; Hatch, Elizabeth E; Mikkelsen, Ellen M; Rothman, Kenneth J; Wise, Lauren A
(, Human Reproduction)
Abstract STUDY QUESTION Do daughters of older mothers have lower fecundability? SUMMARY ANSWER In this cohort study of North American pregnancy planners, there was virtually no association between maternal age ≥35 years and daughters’ fecundability. WHAT IS KNOWN ALREADY Despite suggestive evidence that daughters of older mothers may have lower fertility, only three retrospective studies have examined the association between maternal age and daughter’s fecundability. STUDY DESIGN, SIZE, DURATION Prospective cohort study of 6689 pregnancy planners enrolled between March 2016 and January 2020. PARTICIPANTS/MATERIALS, SETTING, METHODS Pregnancy Study Online (PRESTO) is an ongoing pre-conception cohort study of pregnancy planners (age, 21-45 years) from the USA and Canada. We estimated fecundability ratios (FR) for maternal age at the participant’s birth using multivariable proportional probabilities regression models. MAIN RESULTS AND THE ROLE OF CHANCE Daughters of mothers ≥30 years were less likely to have previous pregnancies (or pregnancy attempts) or risk factors for infertility, although they were more likely to report that their mother had experienced problems conceiving. The proportion of participants with prior unplanned pregnancies, a birth before age 21, ≥3 cycles of attempt at study entry or no follow-up was greater among daughters of mothers <25 years. Compared with maternal age 25–29 years, FRs (95% CI) for maternal age <20, 20–24, 30–34, and ≥35 were 0.72 (0.61, 0.84), 0.92 (0.85, 1.00), 1.08 (1.00, 1.17), and 1.00 (0.89, 1.12), respectively. LIMITATIONS, REASONS FOR CAUTION Although the examined covariates did not meaningfully affect the associations, we had limited information on the participants’ mother. Differences by maternal age in reproductive history, infertility risk factors and loss to follow-up suggest that selection bias may partly explain our results. WIDER IMPLICATIONS OF THE FINDINGS Our finding that maternal age 35 years or older was not associated with daughter’s fecundability is reassuring, considering the trend towards delayed childbirth. However, having been born to a young mother may be a marker of low fecundability among pregnancy planners. STUDY FUNDING/COMPETING INTEREST(S) PRESTO was funded by NICHD Grants (R21-HD072326 and R01-HD086742) and has received in-kind donations from Swiss Precision Diagnostics, FertilityFriend.com, Kindara.com, and Sandstone Diagnostics. Dr Wise is a fibroid consultant for AbbVie, Inc. TRIAL REGISTRATION NUMBER n/a
Wang, Yue, Dessalles, Renaud, and Chou, Tom. Modelling the impact of birth control policies on China’s population and age: effects of delayed births and minimum birth age constraints. Retrieved from https://par.nsf.gov/biblio/10352174. Royal Society Open Science 9.6 Web. doi:10.1098/rsos.211619.
Wang, Yue, Dessalles, Renaud, & Chou, Tom. Modelling the impact of birth control policies on China’s population and age: effects of delayed births and minimum birth age constraints. Royal Society Open Science, 9 (6). Retrieved from https://par.nsf.gov/biblio/10352174. https://doi.org/10.1098/rsos.211619
Wang, Yue, Dessalles, Renaud, and Chou, Tom.
"Modelling the impact of birth control policies on China’s population and age: effects of delayed births and minimum birth age constraints". Royal Society Open Science 9 (6). Country unknown/Code not available. https://doi.org/10.1098/rsos.211619.https://par.nsf.gov/biblio/10352174.
@article{osti_10352174,
place = {Country unknown/Code not available},
title = {Modelling the impact of birth control policies on China’s population and age: effects of delayed births and minimum birth age constraints},
url = {https://par.nsf.gov/biblio/10352174},
DOI = {10.1098/rsos.211619},
abstractNote = {We consider age-structured models with an imposed refractory period between births. These models can be used to formulate alternative population control strategies to China’s one-child policy. By allowing any number of births, but with an imposed delay between births, we show how the total population can be decreased and how a relatively older age distribution can be generated. This delay represents a more ‘continuous’ form of population management for which the strict one-child policy is a limiting case. Such a policy approach could be more easily accepted by society. Our analyses provide an initial framework for studying demographics and how social constraints influence population structure.},
journal = {Royal Society Open Science},
volume = {9},
number = {6},
author = {Wang, Yue and Dessalles, Renaud and Chou, Tom},
}
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