Menarcheal age is a predictor of several complications related to pregnancy and diseases later in life. We aimed to study if menarcheal age is a risk factor for pregnancy-related pelvic pain.
A nested case-control study was conducted within the Danish National Birth Cohort, a cohort of pregnant women, recruited during 1996-2002, and their children. In the second trimester of pregnancy the women provided information about age at menarche and potential confounders. Selection of cases (n?=?2227) was based on self-reported pelvic pain during pregnancy from an interview done 6 months post-partum. The controls (n?=?2588) were randomly selected among women who did not report pelvic pain. We used logistic regression analysis to calculate odds ratios (OR) for pregnancy-related pelvic pain according to age at menarche.
In the cohort, 18.5% of all pregnant women reported pregnancy-related pelvic pain. Compared to women who were 12-14 years old at menarche, the adjusted OR for overall pelvic pain were 1.4 (95% confidence interval [CI] 1.1-1.7) in women 11 years or younger and 0.8 (95%CI 0.6-0.9) in women 15 years or older. The corresponding adjusted OR for severe pelvic pain were 1.6 (95%CI 1.3-2.0) and 0.7 (95%CI 0.6-0.9). When age was analyzed as a continuous variable, the odds for overall and severe pelvic pain decreased with 14% and 16%, respectively, for each increasing year.
The risk of pregnancy-related pelvic pain decreased with increasing menarcheal age in an 'exposure-response' pattern. A low menarcheal age is a risk indicator and may be a risk factor for pregnancy-related pelvic pain.
A possible aetiological link between obesity and certain autoimmune diseases (ADs) has been suggested. We investigated the associations between body mass index (BMI, kg/m2) and 43 ADs.
75,008 women participating in the Danish National Birth Cohort were followed during a median time of 11 years. Diagnoses on ADs were retrieved from the Danish National Patient Register. Cox proportional hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated adjusting for potential confounders (smoking, alcohol, parity and socio-occupational status).
During follow-up, 2430 women (3.2%) developed a total of 2607 new-onset ADs. Risk of any autoimmune disease was increased in obese women (HR, 1.27; 95% CI, 1.11 to 1.46) compared with normal weight women (18.5-=25 kg/m2). Obese women (BMI=30 kg/m2) were at increased risk of sarcoidosis (HR 3.59; 95% CI, 2.31 to 5.57) and type 1 diabetes mellitus (HR 2.67; 95% CI, 1.71 to 4.17). Risk of dermatitis herpetiformis increased by 14% (95% CI, 1% to 30%) per BMI unit. Conversely, risk of celiac disease and Raynaud's phenomenon decreased by 7% (95% CI, 1% to 13%) and 12% (95% CI, 4% to 19%) per BMI unit, respectively. Further associations between BMI and risk of psoriasis, rheumatoid arthritis and Crohn's disease were suggested.
BMI was found to be associated with several Ads. This was most pronounced between obesity and risk of sarcoidosis and and risk of type 1 diabetes mellitus. These novel findings need confirmation and the possible role of adipose tissue-derived immunological changes in the development of autoimmune reactions needs consideration.
We investigated the possible association between body mass index (BMI; weight (kg)/height (m)(2)) and hospitalization or treatment for acute infection in a prospective cohort study. We linked 75,001 women enrolled in the Danish National Birth Cohort from 1996 to 2002, who had information on BMI and a broad range of confounders, to data on infectious diseases and use of antimicrobial agents from the National Patient Register and the Danish Prescription Register. Associations were tested using Cox proportional hazards models. During 12 years of follow-up, we observed a U-shaped association between baseline BMI and later hospitalization for 1) any infectious disease and 2) infections of the respiratory tract, whereas a dose-response relationship was seen for skin infections. The most pronounced associations were seen for acute upper respiratory infections at multiple and unspecified sites (underweight (BMI
Humans are exposed to perfluorinated alkyl acids (PFAAs) from food, drinking water, air, dust, and consumer products. PFAAs are persistent and bio-accumulative. In the present study, we aimed to establish how the serum levels of PFAAs differ according to age, pre-pregnancy body mass index (BMI), previous miscarriages, educational level, country of birth, smoking, and alcohol intake. We included 1438 Danish pregnant nulliparous women from the Aarhus Birth Cohort. The women gave a blood serum sample between week 11 and 13 of pregnancy. Sixteen PFAAs were extracted from serum using solid phase extraction and analyzed by liquid chromatography/tandem mass spectrometry. Multivariable linear regression analysis was used to determine the associations between individual characteristics of the women and their levels of seven PFAAs that were detected in at least 50% of the samples. The total concentration of the PFAAs (?PFAA) was higher in older women. On average, normal weight women had a higher ?PFAA level than underweight, overweight, and obese women. Higher levels were also observed for women without previous miscarriages, women with a high educational level, women born in Denmark (as opposed to women born elsewhere but currently living in Denmark), non-smokers, and women who consumed alcohol before or during pregnancy. These associations were similar for all the studied PFAAs, although the levels of perfluoroundecanoic acid varied more across the categories of age, BMI, education, smoking, and alcohol consumption than any other PFAAs measured.
OBJECTIVE:: We previously reported associations between preeclampsia and the occurrence of metabolic and respiratory diseases in the offspring. In this article we examine whether the associations were due to preeclampsia or factors leading to preeclampsia. STUDY DESIGN:: From 1978 through 2004, we identified 22,264 discordant sib-pairs in Denmark according to prenatal exposure to preeclampsia. Exposed children were compared to their unexposed siblings by using stratified Cox regression to estimate hazard ratios and 95% confidence intervals for metabolic and respiratory diseases. RESULTS:: Exposed children had rather similar risks for metabolic disorders compared to their unexposed siblings. However, when the second child within each sib-pair was exposed, this child had an increased risk for respiratory diseases (hazard ratio, 1.55; 95% confidence interval, 1.20-2.01). CONCLUSION:: Factors leading to preeclampsia may shape susceptibility to metabolic or respiratory diseases in the offspring but a programming effect on respiratory diseases induced by preeclampsia cannot be ruled out.
Thyroid hormones are important developmental factors and levels should be adequate both in the pregnant woman and in the fetus. However, there is no consensus on maternal thyroid test reference limits in early pregnancy.
Estimation of week-to-week changes in and predictors of TSH and free T4 (fT4) reference limits in the first trimester of pregnancy.
Measurement of TSH and fT4 in biobank sera collected in pregnancy weeks 5-19 from a random sample of the Danish National Birth Cohort that enrolled 101 032 pregnant in 1996-2002.
National cohort of pregnant women.
Healthy participants (n = 6671) were identified and individual characteristics retrieved using interview data and data from Danish national health registers.
Reference limits for TSH and fT4 in each first trimester pregnancy week and predictors of these reference limits.
TSH reference limits were very variable. Up to and including week 6, nonpregnancy reference limits could be used. In weeks 9-12, TSH upper reference limit was approximately 0.4 mU/L lower than the nonpregnancy upper limit. The TSH lower reference limit was approximately 0.1 mU/L. fT4 variations were reverse to those of TSH, but changes were small with approximately 4% higher reference limits during the weeks 9-12. TSH upper reference limit was lower in multiparous women and women with lower iodine intake but higher in obese women. fT4 was lower in smokers.
TSH reference limits differ widely in the first trimester of pregnancy. The use of a uniform set of reference limits is an inordinate simplification that will lead to frequent misclassification and possibly to incorrect choice of therapy.
PURPOSE: Preterm birth (PTB) has been associated with a later increased risk of maternal cardiovascular disease (CVD). We hypothesized a more pronounced relation between early or recurrent PTB and maternal CVD risk. METHODS: We related PTB severity (earlier gestational age at delivery) and recurrence (>/=2) among women with births from 1973-1983 in Denmark (n = 427,765) to maternal CVD morbidity or mortality (1977-2006). Birth data were linked to CVD hospitalizations and deaths identified in national registers and data were analyzed using Cox proportional hazards models. RESULTS: Women with a prior PTB had excess CVD after adjustment for age, parity, and education (hazard ratio [HR] = 1.36 [95% confidence interval (CI): 1.31, 1.41]). This was only modestly attenuated when women with preeclampsia or small for gestational age births were excluded, and the relationship was stronger for CVD mortality (HR = 1.98 [1.73, 2.26]). Recurrent PTB was associated with higher CVD morbidity compared to women with one PTB, particularly for ischemic events (HR = 1.78 [1.40, 2.27] vs. 1.22 [1.09, 1.36]). Risk was similarly elevated among women with early, moderate, and late PTB. Sensitivity analysis suggested that confounding by smoking only partly explained these associations. CONCLUSIONS: Women with PTB, especially recurrent PTB, were at increased risk for CVD, suggesting common causes of these conditions.
Asthma exacerbations are among the most frequent causes of hospitalization during childhood, but the underlying mechanisms are poorly understood. We performed a genome-wide association study of a specific asthma phenotype characterized by recurrent, severe exacerbations occurring between 2 and 6 years of age in a total of 1,173 cases and 2,522 controls. Cases were identified from national health registries of hospitalization, and DNA was obtained from the Danish Neonatal Screening Biobank. We identified five loci with genome-wide significant association. Four of these, GSDMB, IL33, RAD50 and IL1RL1, were previously reported as asthma susceptibility loci, but the effect sizes for these loci in our cohort were considerably larger than in the previous genome-wide association studies of asthma. We also obtained strong evidence for a new susceptibility gene, CDHR3 (encoding cadherin-related family member 3), which is highly expressed in airway epithelium. These results demonstrate the strength of applying specific phenotyping in the search for asthma susceptibility genes.
The sequence and timing of permanent tooth eruption is thought to be highly heritable and can have important implications for the risk of malocclusion, crowding, and periodontal disease. We conducted a genome-wide association study of number of permanent teeth erupted between age 6 and 14 years, analyzed as age-adjusted standard deviation score averaged over multiple time points, based on childhood records for 5,104 women from the Danish National Birth Cohort. Four loci showed association at P
Twin and family studies indicate that the timing of primary tooth eruption is highly heritable, with estimates typically exceeding 80%. To identify variants involved in primary tooth eruption, we performed a population-based genome-wide association study of 'age at first tooth' and 'number of teeth' using 5998 and 6609 individuals, respectively, from the Avon Longitudinal Study of Parents and Children (ALSPAC) and 5403 individuals from the 1966 Northern Finland Birth Cohort (NFBC1966). We tested 2 446 724 SNPs imputed in both studies. Analyses were controlled for the effect of gestational age, sex and age of measurement. Results from the two studies were combined using fixed effects inverse variance meta-analysis. We identified a total of 15 independent loci, with 10 loci reaching genome-wide significance (P
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