Age at menarche and risk of asthma: systematic review and meta-analysis

Age at menarche and asthma onset among US girls and women: findings from NHANES, 2001-2018

PURPOSE

To quantitatively estimate the association of age at menarche with the risk of childhood- and adult-onset asthma separately.

METHODS

A retrospective cohort study of 24,282 US girls and women was conducted using continuous National Health and Nutrition Examination Survey (NHANES) data from 2001 to 2018, and Cox proportional hazards regression models with censoring ages of 19 and 79 years were employed to separately estimate hazard ratios of childhood- and adult-onset asthma associated with age at menarche.

RESULTS

Each one-year increase in age at menarche was significantly associated with a 16% (hazard ratio [HR] = 0.84; 95% confidence interval [CI]: 0.77-0.91) decrease in the risk of childhood-onset asthma. Compared with age at menarche of 12-14 years, we observed a 56% (HR = 1.56; 95% CI: 1.19-2.04) increased risk of childhood-onset asthma for early menarche (age at menarche < 12 years) and a 40% (HR = 0.60; 95% CI: 0.32-1.10) decreased risk for late menarche (age at menarche ≥ 15 years). No significant association was noted between age at menarche and adult-onset asthma.

CONCLUSIONS

Early menarche may represent a risk factor for childhood-onset asthma, which indicates the need for timely and effective management of individuals with early menarche to prevent asthma.

A Review of the Epigenetic Clock: Emerging Biomarkers for Asthma and Allergic Disease

DNA methylation (DNAm) is a dynamic, age-dependent epigenetic modification that can be used to study interactions between genetic and environmental factors. Environmental exposures during critical periods of growth and development may alter DNAm patterns, leading to increased susceptibility to diseases such as asthma and allergies. One method to study the role of DNAm is the epigenetic clock-an algorithm that uses DNAm levels at select age-informative Cytosine-phosphate-Guanine (CpG) dinucleotides to predict epigenetic age (EA). The difference between EA and calendar age (CA) is termed epigenetic age acceleration (EAA) and reveals information about the biological capacity of an individual. Associations between EAA and disease susceptibility have been demonstrated for a variety of age-related conditions and, more recently, phenotypes such as asthma and allergic diseases, which often begin in childhood and progress throughout the lifespan. In this review, we explore different epigenetic clocks and how they have been applied, particularly as related to childhood asthma. We delve into how in utero and early life exposures (e.g., smoking, air pollution, maternal BMI) result in methylation changes. Furthermore, we explore the potential for EAA to be used as a biomarker for asthma and allergic diseases and identify areas for further study.

Identifying risk factors for COPD and adult-onset asthma: an umbrella review

BACKGROUND

COPD and adult-onset asthma (AOA) are the most common noncommunicable respiratory diseases. To improve early identification and prevention, an overview of risk factors is needed. We therefore aimed to systematically summarise the nongenetic (exposome) risk factors for AOA and COPD. Additionally, we aimed to compare the risk factors for COPD and AOA.

METHODS

In this umbrella review, we searched PubMed for articles from inception until 1 February 2023 and screened the references of relevant articles. We included systematic reviews and meta-analyses of observational epidemiological studies in humans that assessed a minimum of one lifestyle or environmental risk factor for AOA or COPD.

RESULTS

In total, 75 reviews were included, of which 45 focused on risk factors for COPD, 28 on AOA and two examined both. For asthma, 43 different risk factors were identified while 45 were identified for COPD. For AOA, smoking, a high body mass index (BMI), wood dust exposure and residential chemical exposures, such as formaldehyde exposure or exposure to volatile organic compounds, were amongst the risk factors found. For COPD, smoking, ambient air pollution including nitrogen dioxide, a low BMI, indoor biomass burning, childhood asthma, occupational dust exposure and diet were amongst the risk factors found.

CONCLUSIONS

Many different factors for COPD and asthma have been found, highlighting the differences and similarities. The results of this systematic review can be used to target and identify people at high risk for COPD or AOA.

Long-term health outcomes of early menarche in women: an umbrella review

BACKGROUND

There is limited comprehensive evidence on the potential association between early menarche and subsequent health outcomes.

AIM

To evaluate the existing evidence for the association of early menarche with later health outcomes and assesse the strength and validity of the evidence for these associations.

DESIGN

Umbrella review.

METHODS

We searched PubMed, Web of Science, Embase, CINAHL, Cochrane Database of Systematic Reviews and Google Scholar, and manually screened retrieved references to find systematic reviews and meta-analyses from inception to July 2021. Early menarche was defined by taking into account ethnicity and birth year, and the outcomes were long-term consequences in adulthood.

RESULTS

Thirteen reviews encompassing 283 original articles and over 6.8 million participants from 39 countries across 5 continents were included. In categorical outcomes, early menarche was associated with metabolic syndrome (n = 37 543 pooled adjusted relative risk [aRR] 1.56, 95% confidence interval (CI) 1.33, 1.83; high certainty [Hi]), endometrial cancer (n = 874 188, aRR 1.40, 95% CI 1.17, 1.68; Hi), type 2 diabetes mellitus/impaired glucose tolerance (n = 1 185 444, aRR 1.30, 95% CI 1.19, 1.42; Hi), breast cancer (n = 103 574, aRR 1.19, 95% CI 1.06, 1.33; Hi), death from all causes (n = 152 747, aRR 1.11, 95% CI 1.03, 1.19; Hi), obesity (n = 54 006, aRR 1.68, 95% CI 1.53, 1.84; moderate certainty [Mod]), gestational diabetes mellitus (n = 48 535, aRR 1.32, 95% CI 1.09, 1.58; Mod), hypertension (n = 1 682 689, aRR 1.24, 95% CI 1.20, 1.29; Mod), endometriosis (n = 885 390, aRR 1.22, 95% CI 1.09, 1.37; Mod), ovarian cancer (n = 1 022 451, aRR 1.17, 95% CI 1.04, 1.31; Mod) and asthma (n = 22 859, aRR 1.31, 95% CI 1.09, 1.57; low certainty [Lo]). For continuous outcomes, early menarche was associated with increased body mass index (BMI) in adults ≥40 years of age (n = 121 943, adjusted pooled standardized mean difference [aSMD] 0.30, 95% CI 0.28, 0.32; Mod), BMI in adults <40 years of age (n = 124 728, aSMD 0.39, 95% CI 0.36, 0.43; Mod), serum fasting insulin level (n = 17 020, aSMD 0.52, 95% CI 0.48, 0.57; Mod) and homeostatic model assessment of insulin resistance (n = 7925, aSMD 0.27, 95% CI 0.19, 0.35; Mod).

CONCLUSION

We found varied levels of evidence for the association between early menarche and the development of subsequent health problems. Our results recommend that physicians should pay attention to these associations, as early menarche can be a potential indicator of metabolic disorders and female-specific cancer and cause death in women.

Cohort profile: a prospective Australian cohort study of women's reproductive characteristics and risk of chronic disease from menarche to premenopause (M-PreM)

PURPOSE

Previous studies have identified associations between individual reproductive factors and chronic disease risk among postmenopausal women. However, few have investigated the association of different markers of reproductive function, their interactions and risk factors of chronic disease among women approaching menopause. The Menarche-to-PreMenopause (M-PreM) Study aims to examine the relationship between reproductive factors across the reproductive lifespan and risk indicators for chronic disease among women in their early-to-mid-40s. The purpose of this cohort profile paper is to describe the rationale, study design and participant characteristics of the M-PreM Study.

PARTICIPANTS

Women born in 1973-1978 who participated in the Australian Longitudinal Study on Women's Health (ALSWH) were invited to undertake a clinical or self-administered assessment. A total of 1278 women were recruited from June 2019 to June 2021.

FINDINGS TO DATE

The study measures included functional, cognitive and cardiometabolic tests, anthropometry, spirometry, respiratory health questionnaires, physical activity, sleep patterns, sex hormones, and cardiovascular and metabolic markers; whereas blood and saliva samples were used for the analysis of genetic variants of genes associated with reproductive characteristics and chronic disease. The mean age of the clinic and self-assessed participants was 44.6 and 45.3 years, respectively. The menopausal status of participants was similar between the two arms of the study: 38%-41% premenopausal, 20% perimenopausal, and 36% took oral contraception or hormone replacement therapy. Approximately 80% of women had at least one child and participants reported experiencing pregnancy complications: preterm birth (8%-13% of pregnancies), gestational diabetes (10%) and gestational hypertension (10%-15%).

FUTURE PLANS

The biomedical data collected in the M-PreM Study will be linked to existing ALSWH survey data on sociodemographic factors, health behaviour, reproductive function, and early life factors collected over the past 20 years and health administrative data. The association between reproductive factors and risk indicators of chronic disease will be analysed.

Hormonal Effects on Asthma, Rhinitis, and Eczema

Hormones significantly influence the pathogenesis of asthma, rhinitis, and eczema. This review aims to summarize relevant clinical considerations for practicing allergists and immunologists. The first section reviews the effects of sex hormones: estrogen, progesterone, and testosterone. The second concerns insulin production in the context of type 1 and type 2 diabetes. The third concludes with a discussion of thyroid and adrenal pathology in relationship to asthma, rhinitis, and eczema.

STROBE: The relationship between asthma and early menarche in Korean adolescents

We explored the relationship between asthma and early menarche in a representative sample of Korean adolescents.Web-based self-reported data collected from 2006 to 2015 by the Korean Youth Risk Behavior Web-based Survey were used. Menarche status was divided into "early" (<12 years of age, n = 69,520) and "not early" (≥12 years of age, n = 234,065).Adolescent girls with early menarche exhibited a higher incidence of asthma (8.1% vs 7.4%, P < .001), more frequent school absences because of asthma (10.8% vs 8.7%), and more frequent ≤4-day stretches of school absence (4.6% vs 2.4%) compared with girls with "not early" menarche (all P < .001). Multivariate analysis performed after adjusting for multiple confounders revealed a 1.04-fold (95% confidence interval [CI] 1.00-1.07) greater likelihood of asthma in the early menarche than not early menarche group. In addition, the odds ratios for missing school due to asthma for 1 to 3 and ≥4 days per year in the early menarche group were 1.00 (95% CI 1.00-1.02) and 1.21 (95% CI 1.01-1.46), respectively.Adolescents with early menarche exhibited increased incidences of asthma and severe asthma.

Risk factors for asthma in patients with allergic rhinitis in eastern China

BACKGROUND

Asthma is one of the most common chronic diseases among children and adults and can lead to a high health and socioeconomic burden. Allergic rhinitis (AR) often precedes the development of asthma. This study aims to clarify the risk factors for cocurrent asthma in patients with AR in eastern China.

METHODS

A cross-sectional study of 3739 patients with AR was performed in eastern China. Patients meeting the criteria for AR were evaluated using a skin-prick test (SPT) of 16 common aeroallergens. A logistic regression analysis was used to assess the risk factors of asthma in patients with AR.

RESULTS

The prevalence of asthma in patients with AR was 14.23%. The patients sensitive to dust mites (D. farinae and D. pteronyssinus) had the highest prevalence (76.84% and 73.68%). A significant difference was found in sensitization to four types of allergens (D. farinae, D. pteronyssinus, dog dander, Alternaria alternata) in patients with AR with and without asthma. The strongest risk factor for asthma in patients with AR was an allergy to Aspergillus fumigatus (adjusted OR, 2.42; 95% CI, 1.50-3.90), followed by allergy to D. pteronyssinus (adjusted OR, 2.06; 1.30-3.27), and allergy to dog dander (adjusted OR, 1.92; 1.24-2.97). Various risk factors that are independently associated with asthma in patients with AR were found in different age groups.

CONCLUSIONS

We observed a difference in risk factors in patients with AR with and without asthma. Clarifying the risk factors for asthma in patients with AR is important and may be beneficial to the optimal interventions of asthma.

Trend in age at menarche and its association with body weight, body mass index and non-communicable disease prevalence in Indonesia: evidence from the Indonesian Family Life Survey (IFLS)

Background

In western countries, age at menarche (AAM) is nowadays lower than a century ago, coinciding with increased Body Mass Index (BMI) and prevalence of non-communicable diseases (NCD). This study aimed to determine the time trend in AAM, and its association with BMI and NCD prevalence at later age, in Indonesia.

Methods

We used secondary data of 15,744 women aged 15–65 years from the Indonesian Family Life Survey (IFLS) conducted in the period 1993 to 2015. Multiple linear regression was applied to determine the association of AAM with BMI, and Poisson regression with robust variance for investigating the association of AAM with NCD prevalence ratios. Models were adjusted for age, and effect modification by wealth status, living area, and region was investigated.

Results

AAM has significantly declined from 14.4 (SD:2.1) years of age in the 1940s to 13.4 y (SD:1.5) in the 1990s. AAM was inversely associated with BMI (β: − 0.30 kg/m², 95%CI: − 0.37, − 0.22) and body weight (β: − 0.67 kg, 95%CI: − 0.75, − 0.54), but was not associated with height. After adjustment for age, AAM was not associated with NCD, i.e. hypertension, type 2 diabetes mellitus, liver diseases, asthma, chronic lung diseases, cardiovascular diseases, stroke, cancer, or arthritis. Including BMI in the models did not change the results.

Conclusions

From the 1940s to 1990s, AAM has declined with 1 year in Indonesia. Women with earlier AAM had higher BMI and body weight at later age, but AAM was not associated with NCD prevalence in later life in the Indonesian population. Further longitudinal research is needed to disentangle the direction of causality of the associations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-12995-3.

Population-based study of the association between asthma and exogenous female sex hormone use

OBJECTIVES

Several studies have suggested the influence of exogenous hormones on asthma, but the results are still conflicting. Moreover, there has been little associated research on Asian population. This study aimed to assess the association between use of exogenous female sex hormones and asthma in Korean women.

DESIGN

Korea National Health and Nutrition Examination Survey (KNHANES) is a nationwide programme to assess national health and nutritional status in Korea. A population-based study was conducted to analyse the relationship between self-reported asthma and exogenous hormones using the KNHANES between 2007 and 2012.

PARTICIPANTS

The study sample included 6874 premenopausal and 4912 postmenopausal women aged 30-65.

OUTCOME MEASURES

KNHANES data comprised health interviews and physical examinations. Questionnaires regarding asthma, reproductive factors and exogenous hormones were included.

RESULTS

Among postmenopausal women, 3.4% reported doctor-diagnosed asthma. Hormone replacement therapy (HRT) was associated with increased odds of doctor-diagnosed asthma (OR 1.56; 95% CI 1.04 to 2.35), while the association between HRT and wheeze in the last 1 year was not significant (OR 1.37; 95% CI 0.95 to 1.96). In premenopausal women, the prevalence of asthma was 2.3%. Use of oral contraceptives (OCs) was associated with an increased odds of doctor-diagnosed asthma (OR 1.67; 95% CI 1.01 to 2.76) and wheeze in the last 1 year (OR 1.88; 95% CI 1.31 to 2.69). These associations were dominant among non-obese women (body mass index <25 kg/m²; OR 2.36; 95% CI 1.34 to 4.17 for asthma and OR 2.15; 95% CI 1.43 to 3.23 for wheeze).

CONCLUSIONS

HRT and OCs were associated with increased asthma in postmenopausal and premenopausal women, respectively. The association between OC use and asthma was strong in non-obese premenopausal women.

Identifying environmental exposure profiles associated with timing of menarche: A two-step machine learning approach to examine multiple environmental exposures

BACKGROUND

Variation in the timing of menarche has been linked with adverse health outcomes in later life. There is evidence that exposure to hormonally active agents (or endocrine disrupting chemicals; EDCs) during childhood may play a role in accelerating or delaying menarche. The goal of this study was to generate hypotheses on the relationship between exposure to multiple EDCs and timing of menarche by applying a two-stage machine learning approach.

METHODS

We used data from the National Health and Nutrition Examination Survey (NHANES) for years 2005-2008. Data were analyzed for 229 female participants 12-16 years of age who had blood and urine biomarker measures of 41 environmental exposures, all with >70% above limit of detection, in seven classes of chemicals. We modeled risk for earlier menarche (<12 years of age vs older) with exposure biomarkers. We applied a two-stage approach consisting of a random forest (RF) to identify important exposure combinations associated with timing of menarche followed by multivariable modified Poisson regression to quantify associations between exposure profiles ("combinations") and timing of menarche.

RESULTS

RF identified urinary concentrations of monoethylhexyl phthalate (MEHP) as the most important feature in partitioning girls into homogenous subgroups followed by bisphenol A (BPA) and 2,4-dichlorophenol (2,4-DCP). In this first stage, we identified 11 distinct exposure biomarker profiles, containing five different classes of EDCs associated with earlier menarche. MEHP appeared in all 11 exposure biomarker profiles and phenols appeared in five. Using these profiles in the second-stage of analysis, we found a relationship between lower MEHP and earlier menarche (MEHP ≤ 2.36 ng/mL vs >2.36 ng/mL: adjusted PR = 1.36, 95% CI: 1.02, 1.80). Combinations of lower MEHP with benzophenone-3, 2,4-DCP, and BPA had similar associations with earlier menarche, though slightly weaker in those smaller subgroups. For girls not having lower MEHP, exposure profiles included other biomarkers (BPA, enterodiol, monobenzyl phthalate, triclosan, and 1-hydroxypyrene); these showed largely null associations in the second-stage analysis. Adjustment for covariates did not materially change the estimates or CIs of these models. We observed weak or null effect estimates for some exposure biomarker profiles and relevant profiles consisted of no more than two EDCs, possibly due to small sample sizes in subgroups.

CONCLUSION

A two-stage approach incorporating machine learning was able to identify interpretable combinations of biomarkers in relation to timing of menarche; these should be further explored in prospective studies. Machine learning methods can serve as a valuable tool to identify patterns within data and generate hypotheses that can be investigated within future, targeted analyses.

The mean age of menarche among Chinese schoolgirls declined by 6 months from 2005 to 2014

AIM

This study assessed the trends in the age at menarche in Chinese schoolgirls from the majority Han group and 21 ethnic minorities from 2005 to 2014. We also compared the group differences during the study period.

METHODS

A total of 344 230 girls aged 9-18 years were extracted from the 2005, 2010 and 2014 Chinese National Survey on Students' Constitution and Health. The age at menarche for each subgroup was estimated by probit analysis. The chi-square test and Z-test were used to compare the differences between the groups.

RESULTS

The overall average age at menarche in Chinese schoolgirls decreased from 12.8 years in 2005 to 12.3 years in 2014. The Han girls and girls from 17 ethnic minorities showed decreasing trends in the age at menarche, while four ethnic minorities demonstrated fluctuating increasing trends over time. The gaps in age at menarche between the Han group and 14 of the ethnic minorities became smaller over the study period and were similar by 2014.

CONCLUSION

The overall findings were a decrease in the age at menarche in China and smaller gaps between the majority Han group and ethnic minority groups. Ethnic-specific public health policies are urgently needed on issues such as contraception.

New Perspectives on Difficult Asthma; Sex and Age of Asthma-Onset Based Phenotypes

BACKGROUND

Asthma is a diverse condition that differs with age and sex. However, it remains unclear how sex, age of asthma onset, and/or their interaction influence clinical expression of more problematic adult "difficult" asthma.

OBJECTIVES

To better understand the clinical features of difficult asthma within a real-world clinical setting using novel phenotypic classification, stratifying subjects by sex and age of asthma onset.

METHODS

Participants in a longitudinal difficult asthma clinical cohort study (Wessex AsThma CoHort of difficult asthma; WATCH), United Kingdom (n = 501), were stratified into 4 difficult asthma phenotypes based on sex and age of asthma onset (early <18 years or adult ≥18 years) and characterized in relation to clinical and pathophysiological features.

RESULTS

The cohort had more female participants (65%) but had similar proportions of participants with early- or adult-onset disease. Early-onset female disease was commonest (35%), highly atopic, with good spirometry and strong associations with some physical comorbidities but highest psychophysiologic comorbidities. Adult-onset females also had considerable psychophysiologic comorbidities and highest obesity, and were least atopic. Amongst male subjects, proportionately more had adult-onset disease. Early-onset male disease was rarest (14%) but associated with worst lung function, high smoking, atopy, and fungal sensitization. Despite shortest disease duration, adult-onset males had highest use of maintenance oral corticosteroid, poor lung function, and highest fractional exhaled nitrogen oxide in spite of highest smoking prevalence.

CONCLUSIONS

This study shows that sex, age of asthma onset, and their interactions influence different clinical manifestations of difficult asthma and identifies a greater risk for lung function loss and oral corticosteroid dependence associated with smoking in adult-onset male subjects.

Associations between prenatal exposure to DDT and DDE and allergy symptoms and diagnoses in the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE), South Africa

Dichlorodiphenyl trichloroethane (DDT) is an organochlorine insecticide that is banned internationally except for use as part of Indoor Residual Spraying (IRS) programs to control malaria. Although animal studies show that DDT and its breakdown product dichlorodiphenyl dichloroethylene (DDE) affect the immune system and may cause allergies, no studies have examined this question in populations where IRS is conducted. The aim of our study was to investigate whether prenatal exposure to DDT and DDE is associated with allergy symptoms and diagnose among South African children living in an area where IRS is conducted. To accomplish this aim, we used data from the Venda Health Examination of Mothers, Babies and their Environment (VHEMBE), an ongoing birth cohort study of 752 children born between 2012 and 2013 in the rural Vhembe district of Limpopo, South Africa. We measured maternal peripartum serum concentrations of DDT and DDE, and administered a questionnaire to the caregivers of 658 children aged 3.5 years to collect information on allergy symptoms and diagnoses as well as potential confounders using validated instruments. Using multiple logistic regression models, we found positive associations between DDT and DDE serum concentrations and most of the allergy symptoms and diagnoses. Maternal DDT (Odds Ratio [OR] = 1.5 per 10-fold increase, 95% Confidence interval, CI = 1.0, 2.3) and DDE (OR = 1.4, 95% CI = 0.8, 2.4) serum concentrations were most strongly associated with caregiver report of wheezing or whistling in the chest. Concentrations of DDT and/or DDE were also associated with increased odds of children's chests sounding wheezy during or after exercise, itchy rashes coming and going for at least six months, diagnosis of food allergy, and diagnosis of dust or dust mites allergy but confidence intervals crossed the null. Results suggest that prenatal exposure to DDT, and possibly DDE, is associated with elevated odds of wheezing among children from an IRS area.

Early pubertal maturation and risk of childhood asthma: A Mendelian randomization and longitudinal study

BACKGROUND

Studies on early puberty and incident asthma have reported inconsistent results and are mainly performed in females. In this longitudinal study, we investigated the causal relationship between pubertal maturation and asthma through Mendelian randomization (MR) and explored the joint effect of overweightness and early pubertal maturation on asthma.

METHODS

We used data from the Taiwan Children Health Study with longitudinal follow-ups of 2991 children aged 11-17 years. Six puberty-related single-nucleotide polymorphisms (combined into a weighted allelic score) were used to yield genetic instrumental variables for early puberty. Early pubertal maturation was defined as reaching a certain pubertal stage earlier than the median age for that stage. Incident asthma cases were calculated by excluding children with a history of asthma prior to that age.

RESULTS

The results of MR analysis revealed that early pubertal maturation was associated with active asthma (OR = 1.18; 95% CI: 1.08-1.28); this effect was significant in male children. Early pubertal maturation significantly increased the risk of incident asthma outcomes at 12 and 17 years of age in both sexes (hazard ratio = 2.15; 95% CI: 1.21-3.84). Taking non-overweight and non-early puberty children as the reference group, we observed a synergistic effect of overweightness and early pubertal maturation on asthma risk (OR = 1.08; 95% CI: 1.04-1.11) in children of both sexes.

CONCLUSIONS

Early screening and intervention for obesity are recommended to prevent future early pubertal onset and asthma occurrence.

Early menarche is associated with lower adult lung function: A longitudinal cohort study from the first to sixth decade of life

BACKGROUND AND OBJECTIVE

Early menarche is increasing in prevalence worldwide, prompting clinical and public health interest on its links with pulmonary function. We aimed to investigate the relationship between early menarche and lung function in middle age.

METHODS

The population-based Tasmanian Longitudinal Health Study (born 1961; n = 8583), was initiated in 1968. The 5th Decade follow-up data (mean age: 45 years) included age at menarche and complex lung function testing. The 6th Decade follow-up (age: 53 years) repeated spirometry and gas transfer factor. Multiple linear regression and mediation analyses were performed to determine the association between age at menarche and adult lung function and investigate biological pathways, including the proportion mediated by adult-attained height.

RESULTS

Girls reporting an early menarche (<12 years) were measured to be taller with greater lung function at age 7 years compared with those reporting menarche ≥12 years. By 45 years of age, they were shorter and had lower post-bronchodilator (BD) forced expiratory volume in 1 s (adjusted mean difference: -133 mL; 95% CI: -233, -33), forced vital capacity (-183 mL; 95% CI: -300, -65) and functional residual capacity (-168 mL; 95% CI: -315, -21). Magnitudes of spirometric deficits were similar at age 53 years. Forty percent of these total effects were mediated through adult-attained height.

CONCLUSION

Early menarche was associated with reduced adult lung function. This is the first study to investigate post-BD outcomes and quantify the partial role of adult height in this association.

Drug allergy in children and adults: Is it the double X chromosome?

OBJECTIVE

This article reviews the latest science and epidemiologic studies related to drug allergy in children and adults to explore possible mechanisms related to female propensity for drug allergy.

DATA SOURCES

PubMed literature review, focusing primarily on the last 5 years.

STUDY SELECTIONS

Articles reviewing the science behind female predisposition to atopic and asthmatic conditions and epidemiologic studies reviewing drug allergy and drug-induced anaphylaxis.

RESULTS

Despite adult female predilection for atopic conditions, few laboratory studies explore sex-specific mechanisms in atopic/allergic diseases, and most are focused on autoimmunity and asthma. Drug allergy is more frequently reported in adult females compared with adult males. Adult females are also more likely to have drug-induced anaphylaxis (DIA), although no clear sex predominance has been reported in fatal or severe DIA. Studies in children suggest the reverse picture, with prepubertal males more likely to have drug allergy and DIA than prepubertal girls.

CONCLUSION

Possible explanations for female predisposition for drug allergy are multifactorial and include disproportionate utilization of health care with more exposure to antibiotics or medications, genetic factors related to the X chromosome, epigenetic changes, and discrepant hormonal interactions with immune cells.

The Association Between Female Smoking and Childhood Asthma Prevalence-A Study Based on Aggregative Data

Aims: Socioeconomic and environmental factors influence childhood asthma prevalence across the world. In-depth epidemiological research is necessary to determine the association between asthma prevalence and socio-environmental conditions, and to develop public health strategies to protect the asthmatic children against the environmental precipitators. Our research was based on aggregative data and sought to compare the asthma prevalence between children of two different age-groups across the world and to identify the association among the key socio-environmental conditions with increased childhood asthma prevalence.

Method: We included forty countries with available data on various socio-environmental conditions (2014–2015). Childhood asthma prevalence of two different age groups (6–7 and 13–14 years) were obtained from global asthma report 2014. Because of significant diversities, the selected countries were divided into two groups based on human developmental index (HDI), a well-recognized parameter to estimate the overall socioeconomic status of a country. Robust linear regression was conducted using childhood asthma prevalence as the dependent variable and female smoking prevalence, tertiary school enrollment (TSE), PM₁₀ (particulate matter ≤10 μm in diameter) and gross domestic product (GDP) as predictors.

Results: Asthma prevalence was not different between two age groups. Among all predictors, only female smoking prevalence (reflecting maternal smoking) was associated with asthma prevalence in the countries with lower socio-economic conditions (HDI), but not in the higher HDI group. The results were unchanged even after randomization.

Conclusions: Childhood asthma prevalence did not change significantly with age. Female smoking may have a positive correlation with childhood asthma prevalence in lower HDI countries.

Age at puberty and risk of asthma: A Mendelian randomisation study

BACKGROUND

Observational studies on pubertal timing and asthma, mainly performed in females, have provided conflicting results about a possible association of early puberty with higher risk of adult asthma, possibly due to residual confounding. To overcome issues of confounding, we used Mendelian randomisation (MR), i.e., genetic variants were used as instrumental variables to estimate causal effects of early puberty on post-pubertal asthma in both females and males.

METHODS AND FINDINGS

MR analyses were performed in UK Biobank on 243,316 women using 254 genetic variants for age at menarche, and on 192,067 men using 46 variants for age at voice breaking. Age at menarche, recorded in years, was categorised as early (<12), normal (12-14), or late (>14); age at voice breaking was recorded and analysed as early (younger than average), normal (about average age), or late (older than average). In females, we found evidence for a causal effect of pubertal timing on asthma, with an 8% increase in asthma risk for early menarche (odds ratio [OR] 1.08; 95% CI 1.04 to 1.12; p = 8.7 × 10(-5)) and an 8% decrease for late menarche (OR 0.92; 95% CI 0.89 to 0.97; p = 3.4 × 10(-4)), suggesting a continuous protective effect of increasing age at puberty. In males, we found very similar estimates of causal effects, although with wider confidence intervals (early voice breaking: OR 1.07; 95% CI 1.00 to 1.16; p = 0.06; late voice breaking: OR 0.93; 95% CI 0.87 to 0.99; p = 0.03). We detected only modest pleiotropy, and our findings showed robustness when different methods to account for pleiotropy were applied. BMI may either introduce pleiotropy or lie on the causal pathway; secondary analyses excluding variants associated with BMI yielded similar results to those of the main analyses. Our study relies on self-reported exposures and outcomes, which may have particularly affected the power of the analyses on age at voice breaking.

CONCLUSIONS

This large MR study provides evidence for a causal detrimental effect of early puberty on asthma, and does not support previous observational findings of a U-shaped relationship between pubertal timing and asthma. Common biological or psychological mechanisms associated with early puberty might explain the similarity of our results in females and males, but further research is needed to investigate this. Taken together with evidence for other detrimental effects of early puberty on health, our study emphasises the need to further investigate and address the causes of the secular shift towards earlier puberty observed worldwide.

The association between age at menarche and later risk of gestational diabetes is mediated by insulin resistance

AIMS

Associations have been reported between age at menarche and the later risk of gestational diabetes. However, it is not known whether these associations reflect differences in insulin sensitivity and/or pancreatic β-cell function in pregnancy.

METHODS

We examined this question in women enrolled in the prospective Cambridge Baby Growth Study who recalled their age at menarche in questionnaires during pregnancy. Polynomial logistic and linear regression models were used to relate menarche timing to the risk of gestational diabetes, both unadjusted and adjusted for the Homeostasis Model Assessments of insulin resistance (HOMA IR) and pancreatic β-cell function (HOMA B) at week 28 of pregnancy.

RESULTS

Age at menarche showed a U-shaped association with gestational diabetes risk (linear term: p = 9.5 × 10^-4; quadratic term: p = 1.0 × 10^-3; n = 889; overall model p = 8.1 × 10^-3). Age at menarche showed a negative linear association with insulin resistance (HOMA IR: β = -0.13, p = 5.2 × 10^-4, n = 771), which explained the relationship between age at menarche and gestational diabetes risk (adjusted linear term going from p = 0.03-0.08; adjusted quadratic term going from p = 0.04-0.08; n = 771). Age at menarche also showed a negative linear association with β-cell function (HOMA B: β = -0.11, p = 2.8 × 10^-3, n = 771) but this did not attenuate the relationship between age at menarche and gestational diabetes (adjusted linear term p = 0.02; adjusted quadratic term p = 0.03, n = 771).

CONCLUSIONS

These results suggest that the associations between age at menarche and risk of gestational diabetes and raised pregnancy glucose concentrations may be mediated by insulin resistance.

Precocious Puberty and the Lin28/Let7 Pathway: The Therapeutic Effect of the Nourishing "Yin" and Purging "Fire" Traditional Chinese Medicine Mixture in a Rat Model

The present study aims to investigate the effects of the nourishing “Yin” and purging “Fire” Traditional Chinese Medicine (TCM) herb mixture on precocious puberty and TCM may act through hypothalamic Lin28/let7 pathway expression in the precocious puberty model rats. Meanwhile, to confirm the relationship between Lin28/let7 pathway and puberty by overexpression Lin28a, in the first part of this study, female rats were randomly allocated into untreated controls, the precocious puberty (PP) model group, the PP control group, and the PP + TCM group. Rats on postnatal day 5 were injected danazol to establish the PP model. From days 15 to 35, the rats in the TCM group were given the TCM twice daily. Vaginal opening, sex-related hormones, and body and reproductive organ weights were measured, and the expressions of hypothalamic Lin28a and Lin28b mRNA and let7a and let7b miRNA were detected. In addition, in the second part, the effects of overexpression of Lin28a on the vaginal opening time were evaluated. In the two parts of the study, we found that, at the onset of puberty, a decrease in ovary weight, an increase in the serum levels of luteinizing hormone and progesterone, and increased expression levels of hypothalamic Lin28b mRNA were observed in the PP + TCM group compared to the PP model group. The vaginal opening time was significantly delayed upon overexpression of Lin28a. Above all, the mechanism by which the TCM treats precocious puberty is thus likely to be associated with inhibition of the hypothalamic Lin28/let7 signaling pathway and our findings provide in-depth insight into the relationship between the overexpression of Lin28a gene in the hypothalamus and the onset of puberty.

Addressing unmet needs in understanding asthma mechanisms: From the European Asthma Research and Innovation Partnership (EARIP) Work Package (WP)2 collaborators

Asthma is a heterogeneous, complex disease with clinical phenotypes that incorporate persistent symptoms and acute exacerbations. It affects many millions of Europeans throughout their education and working lives and puts a heavy cost on European productivity. There is a wide spectrum of disease severity and control. Therapeutic advances have been slow despite greater understanding of basic mechanisms and the lack of satisfactory preventative and disease modifying management for asthma constitutes a significant unmet clinical need. Preventing, treating and ultimately curing asthma requires co-ordinated research and innovation across Europe. The European Asthma Research and Innovation Partnership (EARIP) is an FP7-funded programme which has taken a co-ordinated and integrated approach to analysing the future of asthma research and development. This report aims to identify the mechanistic areas in which investment is required to bring about significant improvements in asthma outcomes.

Early menarche and new onset of asthma: Results from the SAPALDIA cohort study

RATIONALE

The association between early menarche and new onset of asthma warrants further investigation in those aged >30 years.

OBJECTIVES

Using data from the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults (SAPALDIA), we investigated whether early menarche was associated with new onset of asthma in women aged 18-60 years at baseline.

METHODS

Our analysis included 2492 women with information on age at menarche and doctor-diagnosed asthma, who had been asthma free at the time of menarche and had complete covariate information. New onset of asthma was defined as newly reported doctor-diagnosed asthma which occurred at least one year after menarche. Asthma incidence and its association with early menarche was analysed using logistic regression, adjusting for age, atopy, smoking, BMI, parental asthma, urbanity, education and study area, and additionally stratifying by atopy and BMI.

RESULTS

After adjustment of relevant confounders, women with early menarche did not have a significantly higher risk of onset of asthma than women without early menarche (OR 1.23, 95% CI 0.85-1.80). Young atopic women with early menarche appeared to have an increased risk of asthma compared with non-atopic women (OR 2.21, 95% CI 0.90-5.43); however, our results did not reach statistical significance.

CONCLUSION

We could not substantiate an association of early menarche with new onset of asthma in this Swiss population-based cohort aged 18-60 years at baseline. Future studies may need to prospectively assess age of menarche to investigate the association with new onset of asthma in those aged >30 years.

Coexistence of asthma and polycystic ovary syndrome: A concise review

Asthma may be associated with polycystic ovary syndrome (PCOS), and possibly patients with PCOS have a more severe type of asthma. The purpose of this systematic literature review is to summarize evidence of a coexistense of PCOS and asthma using the available literature. The search was completed on 01.01.2016. English language articles were retrieved using the search terms 'Asthma' AND 'PCOS', 'Asthma' AND 'systemic inflammation', 'Asthma' AND 'metabolic syndrome', 'asthma' AND 'gynaecology', 'PCOS' AND 'systemic inflammation', 'PCOS' AND 'metabolic syndrome', 'PCOS' AND 'allergy'. Five papers meeting prespecified search criteria were found of which two were registry studies of relevance. The current literature supports a coexistense of PCOS and asthma and gives us an indication of the causes for the possible link between PCOS and asthma. Further research in the area must be conducted to determine the exact nature and magnitude of the association.

Risk and Protective Factors for Childhood Asthma: What Is the Evidence?

To summarize the principal findings on risk and protective factors for childhood asthma, we retrieved systematic reviews on these topics in children (aged 1 to 18 years), up to January 2016, through MEDLINE, EMBASE, CINAHL, SCOPUS, and CDSR. A total of 227 studies were searched from databases. Among those, 41 systematic reviews (SRs) were included: 9 focused on prenatal factors, 5 on perinatal factors, and 27 on postnatal factors. Of these 41 SRs, 83% had good methodological quality, as determined by the Assess Systematic Reviews tool. After reviewing all evidence, parental asthma, prenatal environmental tobacco smoke, and prematurity (particularly very preterm birth) are well-established risk factors for childhood asthma. Current findings do suggest mild-to-moderate causal effects of certain modifiable behaviors or exposures during pregnancy (maternal weight gain or obesity, maternal use of antibiotics or paracetamol, and maternal stress), the perinatal period (birth by Caesarean delivery), or postnatal life (severe respiratory syncytial virus infection, overweight or obesity, indoor exposure to mold or fungi, and outdoor air pollution) on childhood asthma, but this suggestive evidence must be confirmed in interventional studies or (if interventions are not feasible) well-designed prospective studies.

A new childhood asthma phenotype: obese with early menarche

Three concomitant phenomena occur in the later years of childhood: increases in the incidence of asthma, obesity and early menarche. This article is an overview of the current epidemiologic, basic, genetic and epigenetic evidence about this relationship. As a consequence we propose that obese girls who have an early menarche (≤ 11 years of age) constitute a new asthma phenotype in childhood. Future studies need to be carried out in order to find the best control and treatment of this new asthma phenotype.

Sexual maturation protects against development of lung inflammation through estrogen

Increasing levels of estrogen and progesterone are suggested to play a role in the gender switch in asthma prevalence during puberty. We investigated whether the process of sexual maturation in mice affects the development of lung inflammation in adulthood and the contributing roles of estrogen and progesterone during this process. By inducing ovalbumin-induced lung inflammation in sexually mature and immature (ovariectomized before sexual maturation) adult mice, we showed that sexually immature adult mice developed more eosinophilic lung inflammation. This protective effect of "puberty" appears to be dependent on estrogen, as estrogen supplementation at the time of ovariectomy protected against development of lung inflammation in adulthood whereas progesterone supplementation did not. Investigating the underlying mechanism of estrogen-mediated protection, we found that estrogen-treated mice had higher expression of the anti-inflammatory mediator secretory leukoprotease inhibitor (SLPI) and lower expression of the proasthmatic cytokine IL-33 in parenchymal lung tissue and that their expressions colocalized with type II alveolar epithelial cells (AECII). Treating AECII directly with SLPI significantly inhibited IL-33 production upon stimulation with ATP. Our data suggest that estrogen during puberty has a protective effect on asthma development, which is accompanied by induction of anti-inflammatory SLPI production and inhibition of proinflammatory IL-33 production by AECII.

Asthma is Different in Women

Gender differences in asthma incidence, prevalence and severity have been reported worldwide. After puberty, asthma becomes more prevalent and severe in women, and is highest in women with early menarche or with multiple gestations, suggesting a role for sex hormones in asthma genesis. However, the impact of sex hormones on the pathophysiology of asthma is confounded by and difficult to differentiate from age, obesity, atopy, and other gender associated environmental exposures. There are also gender discrepancies in the perception of asthma symptoms. Understanding gender differences in asthma is important to provide effective education and personalized management plans for asthmatics across the lifecourse.

Effect of Nourishing "Yin" Removing "Fire" Chinese Herbal Mixture on Hypothalamic Mammalian Target of Rapamycin Expression during Onset of Puberty in Female Rats

Aim. The present study aims to investigate the effects of nourishing "Yin" removing "Fire" (NYRF) Chinese herbal mixture on puberty onset and hypothalamic mTOR expression in female rats. Materials and Methods. Forty female 20-day-old Sprague-Dawley rats were randomly divided into Chinese herbal mixture (CHM) and normal saline (NS) groups. Rats in CHM and NS were treated with NYRF mixture and normal saline, respectively, from d22. Rats in each group were sacrificed on d28, d31, and d34. Serum luteinizing hormone (LH), follicle stimulating hormone (FSH), and estradiol (E2) levels were analyzed by ELISA. Hypothalamic mTOR mRNA expression levels were determined by RT-PCR and hypothalamic p-mTOR protein levels were assayed by western blot. Results. The vaginal opening time in CHM group was significantly delayed (P < 0.05). On d31, in comparison with NS group, the coefficients of uteri and ovaries, levels of serum LH and E2, and the expression levels of hypothalamic mTOR mRNA and p-mTOR protein were significantly lower in CHM group (P < 0.05). Conclusion. The mechanism by which the nourishing "Yin" removing "Fire" Chinese herbal mixture delays puberty onset may be associated with the inhibition of the hypothalamic mTOR signaling.

Early menarche is associated with increased risk of asthma: Prospective population-based study of twins

AIM

To examine the association between early menarche and risk of post-menarcheal asthma.

METHODS

Using data from two multidisciplinary questionnaire surveys, conducted eight years apart, we prospectively studied 10,648 female twins, 12-41 years of age, from the nationwide Danish Twin Registry. Early menarche was defined as menarche before 12 years of age. We performed a cohort analysis and a co-twin control analysis including twin pairs discordant for incident asthma.

RESULTS

Early menarche was observed in 9.3% of the individuals. The eight-year cumulative incidence of asthma was higher in girls with early menarche compared to girls without early menarche (7.4 vs. 4.5%), OR = 1.71 (1.31-2.22), p < 0.001; also after adjustment for BMI, current age, physical activity, education, and smoking, OR = 1.53 (1.15-2.04), p = 0.003. The unadjusted risk of asthma was increased by 8% (1-15%), p = 0.041 per year earlier menarche occurred. Among 167 twin pairs discordant for incident asthma, there was a non-significant tendency towards early menarche being more common in the asthmatic than the non-asthmatic co-twin (12.0 vs. 9.6%), OR = 1.57 (0.61-4.05), p = 0.350. The risk of asthma was not uniform in discordant monozygotic and dizygotic twins.

CONCLUSION

Early menarche is associated with increased risk of asthma among Danish female twins independently of BMI, age, physical activity, educational level and smoking. Results indicate a complex relationship possibly mediated through innate and non-genetic effects.