Adolescent pregnancy is associated with osteoporosis in postmenopausal women

Causal relationship between reproductive factors and female bone density: a univariate and multivariate mendelian randomization study

Objective

Observational studies have found associations between reproductive factors and bone density in women. However, the causal relationships are not well understood. This study aims to investigate whether various reproductive factors are causally related to bone density at different skeletal sites using both univariable and multivariable Mendelian randomization (MR) methods.

Methods

The study incorporated four reproductive factors, namely, age at menarche (AAM), age at first live birth (AFB), age at menopause (ANM), and age at last live birth (ALB), as well as five distinct skeletal sites, including bone mineral density (BMD), heel calcaneus BMD, ultradistal forearm bone mineral density (FA-BMD), lumbar spine bone mineral density (LS-BMD), and femoral neck bone mineral density (FN-BMD). Univariable two-sample MR and multivariable MR analyses were conducted using data from published genome-wide association studies (GWASs). A total of 150 single nucleotide polymorphisms (SNPs) associated with the four reproductive factors were extracted from GWAS databases. The primary statistical analysis method utilized in this study was the inverse variance weighted (IVW) method.

Results

In the univariate MR analysis, we observed causal connections between four reproductive factors and bone density. Specifically, AAM had a significant impact on BMD and heel calcaneus BMD. Age at first live birth was negatively associated with FA-BMD. Age at last live birth showed a negative correlation with BMD and heel calcaneus BMD. ANM exhibited positive associations with BMD, heel calcaneus BMD, FA-BMD, and LS-BMD. Subsequently, we performed a multivariable MR analysis to examine the combined effects of multiple variables, which confirmed the persistence of associations between age at menopause and bone density at various sites. Additionally, we found a negative correlation between age at last live birth and heel calcaneus BMD.

Conclusion

This study offers a fresh perspective on the prevention of osteoporosis in women, explicitly stating that reproductive factors such as early menopause and late childbirth play a significant predictive role in individual bone density decline. Therefore, when developing osteoporosis screening and management protocols, reproductive factors should be included for a more comprehensive guidance of clinical practice.

Does adolescent pregnancy affect postmenopausal bone mineral density?

Aim: This study aims to investigate the effect of adolescent pregnancies on bone mineral density in the postmenopausal period and to contribute to this controversial issue. Material and Method: Our study included 70 women at postmenopausal ages. The participants were divided into two groups. Thirty-five women with a history of pregnancy in adolescence were considered group 1, and 35 women without a history of pregnancy were considered group 2. The BMD was measured in the total hip, femoral neck, and lumbar spine. The data were compared using SPSS version 26, and p

Socio-demographic correlates and trends in the timing of the onset of parenthood among women of reproductive age in Ghana: evidence from three waves of the demographic and health surveys

BACKGROUND

Childbearing is one of the central events in a woman's life and the age at which this event occurs has important health, socioeconomic and fertility implications for her.   Methods: We used three waves of the Ghana Demographic and Health Surveys (GDHS) from the individual files of married women aged 15 to 49 years old to explore the trends in the timing of the onset of parenthood among women in Ghana. The Cox proportional hazard model was used to assess the effect of socio-demographic factors on the birth experience of women.   Results: Results showed the median age of the women increases from 17 years in 1998 to 19 years in 2014. Further, results showed that women with secondary education had 0.67, 0.89- and 0.77-times lower hazard risk of early birth than women without any formal education in 1988, 1998, and 2014 respectively. The hazard risk of early childbirth consistently decreased as age increased in all the years of surveys except in the case of the age group 40-44 in 1988, 1998 and 2014.   Conclusions: This study showed that the timing of first childbirth is changing in the direction of a late childbirth regime in Ghana and could facilitate improvement on individual health, job stability and higher level of education. Efforts should be channeled to sensitizing women on the importance of delaying childbearing.

Association of age at first birth and risk of non-alcoholic fatty liver disease in women: evidence from the NHANES

BACKGROUND

Numerous studies have suggested that age at first birth (AFB) is inversely associated with metabolic diseases, but positively associated with liver cancer in women. Non-alcoholic fatty liver disease (NAFLD) is a canonical example of metabolic dysfunction and inflammation-based liver disease, while the association between AFB and the risk of NAFLD remains unclear. We aimed to investigate the association between AFB and the odds of NAFLD in women.

METHODS

Women older than 20 years at the time of the survey were analyzed using National Health and Nutrition Examination Survey (NHANES) data from 1999 to 2018 in the US. AFB was obtained with self-administered questionnaires. NAFLD was diagnosed as fatty liver index (FLI) ≥ 60. Odds ratios (ORs) and 95% confidence intervals (CI) were estimated using logistic regression models.

RESULTS

Of the 12,188 women included in this study, 5670 (46.5%) had NAFLD. Compared to individuals with AFB of 30-32 years old (reference group), the fully adjusted ORs and 95% CI in women with AFB < 18, 18-20, 21-23, and 24-26 years were 1.52 (95% CI 1.14, 2.03), 1.60 (95% CI 1.21, 2.11), 1.40 (95% CI 1.06, 1.84), and 1.33 (95% CI 1.01-1.76), respectively. Yet there was no significant difference between AFB of 27-29, 33-35, or > 35 years compared to the reference group.

CONCLUSIONS

Women with younger AFB have higher odds of NAFLD in later life. Policymakers should consider focusing on those with earlier AFB for screening and prevention of NAFLD.

Impact of Adolescent Pregnancy on Bone Density in Underprivileged Pre-Menopausal Indian Women

High prevalence (31.5%) of adolescent pregnancies (AP) have been reported in India. Reports suggest that pregnancy during adolescence may have deleterious effects on peak bone mass. Very few studies have described the long-term effects of a history of AP on bone mass. The objective of this study was to compare bone mineral density (BMD) and bone geometry of premenopausal women with first childbirth during adolescence (i.e., before age of 19 years) or after 20 years. A cross-sectional study was conducted in 242 women (age 28.0-54.5 years) from Pune, India (November, 2015 to November, 2017). Women were divided into 2-groups: Group-1: women-who had 1st-pregnancy and childbirth before 19 years of age (AP n = 131) and Group-2: women-who had 1st pregnancy after 20 years of age (non-AP n = 111). Demographic data, anthropometric measurements, and biochemical tests were performed using standard protocols. Physical activity and nutrient intakes were recorded using validated questionnaires. Areal BMD and bone geometry were measured using Dual-Energy-Absorptiometry-DXA (Lunar-iDXA, GE Healthcare) and peripheral-quantitative-computed-tomography-pQCT (XCT2000, Stratec Inc.). Mean age of the study group was 37 ± 4.6 years; in women from group-1 mean age at first delivery was 16.9 ± 1.6 years as against 22.6 ± 3.1 years in group-2. Both groups were similar in body mass index and socioeconomic status. pQCT measured radial diaphyseal cortical thickness (1.97 ± 0.3 mm vs 1.88 ± 0.3 mm resp., p = 0.016, periosteal circumference (38.0 ± 3.6 mm vs 36.7 ± 2.5 mm, resp. p = 0.016), total bone area (114.3 ± 24.8 mm2 vs 108.7 ± 14.7 mm2 resp. p = 0.026) and stress-strain index (SSI = 217 ± 75 vs 201 ± 40 mm3 resp. p = 0.042) were significantly higher in group-1 than group-2. After adjusting for anthropometric and lifestyle parameters, pQCT measured cortical thickness (1.98 ± 0.03 mm in group-1, 1.87 ± 0.03 mm group-2, p = 0.01, mean ± SE) and iDXA derived aBMD at forearm were still significantly higher (0.599 ± 0.006 g/cm3 vs 0.580 ± 0.006 g/cm3, p = 0.023) in Group-1. Our data suggest that women with a history of adolescent pregnancy had better bone geometry and higher aBMD at radius in later years. We speculate that early exposure to pregnancy resulted in higher aBMD at the radius and induced changes at radial diaphysis with bones becoming thicker and wider among these women.

Recovery of the maternal skeleton after lactation is impaired by advanced maternal age but not by reduced IGF availability in the mouse

Background

Lactation results in substantial maternal bone loss that is recovered following weaning. However, the mechanisms underlying this recovery, and in particular the role of insulin-like growth factor 1 (IGF-I), is not clear. Furthermore, there is little data regarding whether recovery is affected by advanced maternal age.

Methods

Using micro-computed tomography, we studied bone recovery following lactation in mice at 2, 5 and 7 months of age. We also investigated the effects of reduced IGF-I availability using mice lacking PAPP-A2, a protease of insulin-like growth factor binding protein 5 (IGFBP-5).

Results

In 2 month old mice, lactation affected femoral trabecular and cortical bone, but only cortical bone showed recovery 3 weeks after weaning. This recovery was not affected by deletion of the Pappa2 gene. The amount of trabecular bone was reduced in 5 and 7 month old mice, and was not further reduced by lactation. However, the recovery of cortical bone was impaired at 5 and 7 months compared with at 2 months.

Conclusions

Recovery of the maternal skeleton after lactation is impaired in moderately-aged mice compared with younger mice. Our results may be relevant to the long-term effects of breastfeeding on the maternal skeleton in humans, particularly given the increasing median maternal age at childbearing.

Pregnancy and lactation, a challenge for the skeleton

In this review we discuss skeletal adaptations to the demanding situation of pregnancy and lactation. Calcium demands are increased during pregnancy and lactation, and this is effectuated by a complex series of hormonal changes. The changes in bone structure at the tissue and whole bone level observed during pregnancy and lactation appear to largely recover over time. The magnitude of the changes observed during lactation may relate to the volume and duration of breastfeeding and return to regular menses. Studies examining long-term consequences of pregnancy and lactation suggest that there are small, site-specific benefits to bone density and that bone geometry may also be affected. Pregnancy- and lactation-induced osteoporosis (PLO) is a rare disease for which the pathophysiological mechanism is as yet incompletely known; here, we discuss and speculate on the possible roles of genetics, oxytocin, sympathetic tone and bone marrow fat. Finally, we discuss fracture healing during pregnancy and lactation and the effects of estrogen on this process.

Competition for nutrients in pregnant adolescents: consequences for maternal, conceptus and offspring endocrine systems

The competition for nutrients that arises when pregnancy coincides with continuing or incomplete growth in young adolescent girls increases the risk of preterm delivery and low birthweight with negative after-effects for mother and child extending beyond the perinatal period. Sheep paradigms involving nutritional management of weight and adiposity in young, biologically immature adolescents have allowed the consequences of differential maternal growth status to be explored. Although nutrient reserves at conception play a modest role, it is the dietary manipulation of the maternal growth trajectory thereafter which has the most negative impact on pregnancy outcome. Overnourishing adolescents to promote rapid maternal growth is particularly detrimental as placental growth, uteroplacental blood flows and fetal nutrient delivery are perturbed leading to a high incidence of fetal growth restriction and premature delivery of low birthweight lambs, whereas in undernourished adolescents further maternal growth is prevented, and depletion of the maternal body results in a small reduction in birthweight independent of placental size. Maternal and placental endocrine systems are differentially altered in both paradigms with downstream effects on fetal endocrine systems, organ development and body composition. Approaches to reverse these effects have been explored, predominantly targeting placental growth or function. After birth, growth-restricted offspring born to overnourished adolescents and fed to appetite have an altered metabolic phenotype which persists into adulthood, whereas offspring of undernourished adolescents are largely unaffected. This body of work using ovine paradigms has public health implications for nutritional advice offered to young adolescents before and during pregnancy, and their offspring thereafter.

An Evaluation of the Association of Reproductive History and Multiple Births during Adolescence with Postmenopausal Osteoporosis

Introduction Osteoporosis is the most common metabolic bone disease characterized by low bone mass. Reproductive factors are known to affect bone mineral density (BMD). Calcium loss from maternal bone and decreased BMD have been observed especially during pregnancy and lactation, although this loss has been reported to recover within 6 – 12 months. There is no consensus on whether the effect of reproductive factors on the bone is positive or negative. The adolescent period is important for total bone mass, and total bone mass is significant in osteoporosis. The aim of this study was to investigate the effect of first gestational age, multiple births during adolescence, interpregnancy interval and reproductive history such as duration of breastfeeding on bone mineral density in postmenopausal women.

Materials and Methods BMD was measured in a total of 196 postmenopausal patients and in accordance with the results, analysis was made of three groups as normal, osteopenia and osteoporosis. Dual Energy X-Ray Absorptiometry (DEXA) was used to take the lumbar, femoral and total bone BMD measurements.

Results No statistically significant difference was determined between the groups in respect of total breastfeeding time (p = 0.596). It was detected that an increased interpregnancy interval decreased the risk of osteoporosis. In patients with osteoporosis, the mean interpregnancy interval was 1.4 ± 0.73 years, while it was longer in patients with osteopenia (1.92 ± 1.20) and normal BMD (2.45 ± 1.77) (p = 0.005). While no effect was determined of the first gestational age on BMD, in the univariate logistic regression analysis, multiple births in the adolescent period were seen to increase the risk of osteoporosis 6.833-fold (p = 0.001, OR = 6.833, 95% CI = 2.131 – 21.908; p = 0.001). The increase in the age of menopause was determined to decrease the risk of osteoporosis (OR = 0.911, 95% CI = 0.843 – 0.985; p = 0.019).

Conclusion Having frequent births throughout the whole reproductive age and having more than one child in adolescence has an adverse effect on postmenopausal bone mineral densities.

Effect of Childbirth Age on Bone Mineral Density in Postmenopausal Women

BACKGROUND

In postmenopausal women, there is rapid bone loss due to estrogen depletion. In women, reproductive factors such as age at menarche, breastfeeding, and parity are considered risk factors of osteoporosis. Many reports suggest that obesity is associated with a reduced risk of osteoporosis. This nationwide, population-based study aims to identify the association between maternal age and osteoporosis risk in postmenopausal women of different obesity classifications.

METHODS

We assessed data from the Korean National Health and Nutrition Examination Survey 2010-2012. The study included 1,328 postmenopausal women, after excluding women with missing data for reproductive history among 4,546 postmenopausal women in the survey. Multivariate regression was used to identify the association between childbirth age and postmenopausal bone mineral density after adjustments for confounding factors.

RESULTS

The prevalence of postmenopausal osteoporosis was 35.24% (n = 468). After dividing the subjects into obese and non-obese groups based on body mass index (BMI) and waist circumference, there were significant differences between non-osteoporosis and osteoporosis groups with regard to age at first childbirth, age at last childbirth, and parity in the BMI-based general obesity group. The prevalence of osteoporosis was highest in women older than 35 years old at last childbirth. The prevalence of osteoporosis was also greater in women with parity ≥ 4 compared to those with lower parity levels.

CONCLUSION

Postmenopausal women of older age at last childbirth and higher parity were at increased risk of osteoporosis in the BMI-based non-general obesity group.

Comparison of Measurements of Bone Mineral Density in Young and Middle-Aged Adult Women in Relation to Dietary, Anthropometric and Reproductive Variables

The objective of this study was to compare current measurements of bone mineral density (BMD) of the lumbar spine (LS), femoral neck (FN), and total femur (TF) regions with initial values recorded 12 years ago in women from Northwest Mexico, and evaluate their correlation with dietary, anthropometric, and reproductive variables. BMD was assessed by Dual-energy X-ray absorptiometry. Participants were grouped as follows: Nulliparous (G1); women who were mothers 12 years ago (G2); and women who were nulliparous 12 years ago, but are now mothers (G3). In all three groups, current LS BMD was higher than initial (p ≤ 0.05) and current TF BMD in G2 was higher than initial values (p ≤ 0.05). When comparing current FN and TF BMD among the three groups, G2 had higher values than G3 (p ≤ 0.05). G2 also showed higher LS BMD than G1 and G3 (p = 0.006). Age at menarche was inversely-correlated with FN and TF BMD in G1 (p < 0.01), while the body mass index (BMI) correlated positively with all three bone regions in G2 (p < 0.05). This study shows that in women without and with children, age at menarche, BMI, and age were factors associated to BMD in healthy subjects in reproductive age.

The relationships between timing of first childbirth, parity, and health-related quality of life

PURPOSE

A few studies have investigated the relationship between age at first childbirth and health-related quality of life (HRQoL). This study examined the relationship between age at first childbirth and HRQoL and whether parity mediates this timing of the first childbirth-HRQoL relationship in women aged 50 years or above.

METHODS

The study population included 5146 parous women ≥ 50 years in the cross-sectional survey, the Korea National Health and Nutrition Examination Survey 2010-2012. HRQoL was evaluated by the EuroQol five-dimensional descriptive system. Participants were grouped according to quartiles of age at first childbirth (ranges: 13-21, 22-23, 24-25, and 26-44 years). This study used linear regression analysis to examine the relationship between age at first childbirth and HRQoL and on each dimension. Mediation analysis was used to examine the contribution of age at first childbirth to HRQoL and to each dimension.

RESULTS

This study found the increasing pattern of HRQoL across quartiles of age at first childbirth (P for trend = 0.030). Odds of problems in self-care and anxiety/depression dimensions significantly increased across the quartiles. Women with later age at first childbirth tended to have better HRQoL (B = 0.352, P = 0.003); parity significantly contributed to this relationship. Decreasing parity accounted for 33.5% of the relationship between late first childbirth and increased HRQoL. Early age at first childbirth significantly increased odds of the mobility problem through increasing parity.

CONCLUSIONS

Women of an early age at first childbirth tended to have lower HRQoL through giving more deliveries. Our findings suggest that more attention needs to be given to women with early pregnancy and more delivery to prevent impaired HRQoL.

Timing of first childbirth and age-related cataract

OBJECTIVE

No studies investigated the effects of age at first childbirth on cataract formation. This study was performed to determine the relationships of age at first childbirth to age-related cataract in postmenopausal women.

METHODS

Study population included 7,021 postmenopausal women in the Korea National Health and Nutrition Examination Survey, 2008 to 2012. Participants were subdivided in quartiles according to the age at first childbirth as follows: 13 to 21, 22 to 23, 24 to 25, and 26 to 44 years. We used odds ratios (ORs) and 95% confidence intervals (CIs) to address the relationships between age at first childbirth and age-related cataract with adjustments for confounders.

RESULTS

Mean participants' age and age at first childbirth were 64.4 and 23.6 years, respectively. The prevalence of any subtype of age-related cataract was 64.9%. Nuclear cataract prevalence was significantly higher in postmenopausal women with later age at first childbirth (24-25 and 26-44 years) compared with those with the earliest age at first childbirth (13-21 years): ORs (95% CIs) were 1.23 (1.05-1.45) and 1.24 (1.05-1.46), respectively. A significant linear trend across quintile was observed (P = 0.006). Age at first childbirth linearly 4% (OR 1.04, 95% CI 1.01-1.06) and 2% (OR 1.02, 95% CI 1.00-1.04) increased risk for nuclear and cortical cataract formation, respectively. The population-attributable fraction of nuclear cataract caused by the first childbirth at 24 years or later was 4.9% (95% CI 1.20%-8.59%, P = 0.009).

CONCLUSIONS

Later age of first childbirth was independently associated with higher risks of nuclear and cortical cataract in postmenopausal women. Further prospective studies are needed to elucidate the role of age at first childbirth in developing age-related cataract.

Age at First Childbirth and Hypertension in Postmenopausal Women

Whether age at first childbirth has an effect on hypertension incidence is unclear. The objectives of this study were to examine the relationship between age at first childbirth and hypertension and to examine whether degree of obesity, measured as body mass index, mediates age at first childbirth-related hypertension in postmenopausal women. This study analyzed 4779 postmenopausal women data from the Korea National Health and Nutrition Examination Survey 2010 to 2012. Logistic regression analyses were used to investigate relationship between age at first childbirth and hypertension. Mediation analysis was performed to examine the contribution of body mass index to age at first childbirth-related hypertension. Mean of participants’ age at first childbirth and current age were 23.8 and 63.4 years, respectively. The prevalence of hypertension was 51.1%. Age at first childbirth was significantly associated with the prevalence of hypertension (odds ratio, 0.963; 95% confidence interval, 0.930–0.998; P =0.036). Women with age at first childbirth ≤19 years had significantly higher risk of hypertension (odds ratio, 1.61; 95% confidence interval, 1.17–2.23; P =0.004) compared with those >19 years. Multivariable-adjusted prevalence of hypertension was significantly lower in women who delivered the first infant at 20 to 24 (45.5%), 25 to 29 (46.1%), and ≥30 (39.9%) years compared with those at ≤19 years (58.4%). Body mass index completely mediated age at first childbirth–hypertension relationship (indirect effect: odds ratio, 0.992; 95% confidence interval, 0.987–0.998; P =0.008). Age at first childbirth was significantly associated with hypertension in postmenopausal women. Body mass index mediated the effects of age at first childbirth on hypertension.

Impact of adolescent pregnancy on hypertension in postmenopausal women

OBJECTIVE

Several studies have reported the detrimental effects on maternal health due to pregnancy during adolescence, but no studies have reported the influence of adolescent pregnancy on blood pressure in women's later life.

METHOD

We investigated whether there was an association between adolescent pregnancy and the risk of hypertension in Korean postmenopausal women. This study used the data of 2538 postmenopausal women from the Korean National Health and Nutrition Examination Survey in 2010-2011. Multivariate logistic regression analyses were used to evaluate the independent association between adolescent pregnancy and hypertension by adjusting for potential confounding factors.

RESULTS

Postmenopausal women with a history of adolescent pregnancy had a higher prevalence of hypertension than those without a history of adolescent pregnancy. After fully adjusting for potential confounding factors such as age, lifestyle, sociodemographic factors, known hypertension risk factors, and reproductive factors, a history of adolescent pregnancy was significantly associated with hypertension (odds ratio, 1.702; 95% confidence interval, 1.125-2.574).

CONCLUSION

This study showed that a history of adolescent pregnancy is significantly and independently associated with a higher risk of hypertension in postmenopausal women.

Association between delivery at an advanced maternal age and osteoporosis in elderly Korean women

Although several reproductive factors have been associated with low bone mineral density (BMD) in elderly women, few studies have evaluated the long-term effects of delivery at a high-risk maternal age on BMD. Using nationally representative survey data collected from 736 women aged 65 years or older, we evaluated the relationship between delivery during adolescence or at an age of 35 years or older and osteoporosis in elderly women. Data regarding demographic and socioeconomic characteristics, medical history, lifestyle risk factors, reproductive history, and history of osteoporosis and fracture were collected by administration of self-report questionnaires. Anthropometric data and BMD were measured in accordance with standardized guidelines. Independent determinants of BMD were identified by stepwise multiple linear regression analysis, and the resulting model was used to evaluate the risk of osteoporosis according to delivery during adolescence or at an advanced age. Of the 736 subjects, 426 (60.1 %) were found to have osteoporosis (T score ≤ -2.5), and 19.2 and 38.9 % reported delivery during adolescence and at an advanced age, respectively. The incidence of delivery during adolescence or at an advanced age was significantly higher in subjects with osteoporosis than in those without osteoporosis. After adjustment for covariates, multiple logistic regression analysis revealed that elderly women with a history of delivery at an advanced maternal age are at an increased (2.164-fold greater) risk of osteoporosis (95 % confidence interval 1.109-4.223) compared with elderly women without a history of delivery at an advanced age. However, a history of delivery during adolescence did not affect the risk.

Age at First Delivery and Osteoporosis Risk in Korean Postmenopausal Women: The 2008-2011 Korea National Health and Nutrition Examination Survey (KNHANES)

It has been reported in several studies that there may be a significant correlation between reproductive history and the risk of osteoporosis due to the effect of estrogen. Under this hypothesis, however, it is unclear whether the age at first delivery has any major influences on the risk of osteoporosis. Therefore, this study aimed to investigate the relationship between the age at first delivery and the risk of osteoporosis in Korean menopausal women. This study was performed using data from the 2008–2011 Korea National Health and Nutrition Examination Survey and included 2,530 Korean postmenopausal women. The diagnosis of osteoporosis was made using the World Health Organization T-score criteria (T-score ≤ -2.5, at the femoral neck or lumbar spine). Participants were categorized into 3 groups according to age at first delivery: ≤23, 24–29, and ≥30 years. Older age, lower body mass index, lower calcium intake, later menarche, and earlier menopause increased the risk of osteoporosis, whereas hormone therapy and oral contraceptive use were associated with a decreased risk of osteoporosis. Postmenopausal women whose first delivery occurred at age 24–29 years were shown to have a significantly increased risk of osteoporosis (odds ratio, 2.124; 95% confidence interval, 1.096–4.113; P = 0.026) compared to those who first gave birth after the age of 30 years. These findings suggest that postmenopausal women whose first delivery occurred in their mid to late 20s, a period during which bone mass slowly accumulates to the peak, are at an increased risk of osteoporosis.

Reductions in heel bone quality across gestation are attenuated in pregnant adolescents with higher prepregnancy weight and greater increases in PTH across gestation

Few studies have examined the effect of maternal calcium intake and vitamin D status on bone health across gestation in pregnant adolescents. This study aimed to characterize maternal bone quality and determinants of bone-quality change across gestation in pregnant adolescents. Healthy pregnant adolescents (n = 156; aged 13 to 18 years) with singleton pregnancies and at 12 to 30 weeks gestation at enrollment were recruited from two urban maternity clinics in Baltimore, MD, and Rochester, NY, for this prospective longitudinal study. Maternal serum was collected at midgestation and at delivery for assessment of bone biomarkers and calcitropic hormones. Maternal bone quality (assessed by heel ultrasound) and sonographic fetal biometry were measured up to three times across pregnancy. Racially diverse teens (64.7% African American, 35.3% white) were followed from 21.0 (interquartile range [IQR] 17.3, 27.0) weeks of gestation until delivery at 40.0 (IQR 39.0, 40.7) weeks. Significant decreases in calcaneal speed of sound (SOS), broadband ultrasound attenuation (BUA), and quantitative ultrasound index (QUI) (-9.2 ± 16.1 m/s, -3.2 (-8.0, 2.1) dB/MHz and -5.3 ± 8.8, respectively) were evident across pregnancy. Multivariate analysis controlling for baseline measures and measurement intervals was used to identify independent predictors of normalized (per week) calcaneal bone loss. Weekly decreases in bone quality were not significantly associated with maternal calcium intake or 25(OH)D concentration. Greater weekly reductions in calcaneal bone quality were evident in teens with lower prepregnancy weight (BUA, p = 0.006 and QUI, p = 0.012) and among those with lower weekly increase in PTH (SOS, p = 0.046). Overall, significant decreases in calcaneal bone quality occurred across pregnancy in adolescents, but the magnitude of this loss was attenuated in those with greater prepregnancy weight and weekly increases in PTH. Further studies are needed to understand the role of elevated PTH and greater prepregnancy weight in preserving adolescent bone during pregnancy.

Early maternal age at first birth is associated with chronic diseases and poor physical performance in older age: cross-sectional analysis from the International Mobility in Aging Study

BACKGROUND

Early maternal age at first birth and elevated parity may have long-term consequences for the health of women as they age. Both are known risk factors for obstetrical complications with lifelong associated morbidities. They may also be related to diabetes and cardiovascular disease development.

METHODS

We examine the relationship between early maternal age at first birth, defined as ≤18 years of age, multiparity (>2 births), and poor physical performance (Short Physical Performance Battery≤8) in community samples of women between 65 and 74 years of age from Canada, Albania, Colombia, and Brazil (N=1040). Data were collected in 2012 to provide a baseline assessment for a longitudinal cohort called the International Mobility in Aging Study. We used logistic regression and general linear models to analyse the data.

RESULTS

Early maternal age at first birth is significantly associated with diabetes, chronic lung disease, high blood pressure, and poor physical performance in women at older ages. Parity was not independently associated with chronic conditions and physical performance in older age. After adjustment for study site, age, education, childhood economic adversity and lifetime births, women who gave birth at a young age had 1.75 (95% CI: 1.17-2.64) the odds of poor SPPB compared to women who gave birth>18 years of age. Adjustment for chronic diseases attenuated the association between early first birth and physical performance. Results were weaker in Colombia and Brazil, than Canada and Albania.

CONCLUSIONS

This study provides evidence that adolescent childbirth may increase the risk of developing chronic diseases and physical limitations in older age. Results likely reflect both the biological and social consequences of early childbearing and if the observed relationship is causal, it reinforces the importance of providing contraception and sex education to young women, as the consequences of early pregnancy may be life-long.

Why Are Childhood Family Factors Associated With Timing of Maturation? A Role for Internal Prediction

Children, particularly girls, who experience early familial adversity tend to go on to reach sexual maturity relatively early. This feature of adolescent development is believed to be an evolved strategy that arose because individuals with genes that caused them to mature relatively early under certain conditions left behind more descendants than those who did not. However, although much has been done to uncover the psychological and physiological mechanisms underlying this process, less attention has been paid to the evolutionary reasons behind why it might be advantageous. It has previously been suggested that this strategy evolved because early familial adversity accurately indicated later environmental adversity, under which conditions early reproduction would likely maximize evolutionary fitness. In this article, we contrast this “external prediction” model with an alternative explanation, which builds on the existing explanation and is mutually compatible with it but also distinct from it. We argue that accelerated development is advantageous because early adversity detrimentally affects the individual’s body, increasing later morbidity and mortality; individuals may adapt to this internal setback by accelerating their development. Unlike the external prediction model, this “internal prediction” relies not on temporal environmental continuity but on long-term effects of early circumstances on the body.