| 1. |
- Ek, Weronica E., et al.
(author)
-
Tea and coffee consumption in relation to DNA methylation in four European cohorts
- 2017
-
In: Human Molecular Genetics. - : Oxford University Press. - 0964-6906 .- 1460-2083. ; 26:16, s. 3221-3231
-
Journal article (peer-reviewed)abstract
- Lifestyle factors, such as food choices and exposure to chemicals, can alter DNA methylation and lead to changes in gene activity. Two such exposures with pharmacologically active components are coffee and tea consumption. Both coffee and tea has been suggested to play an important role in modulating disease-risk in humans by suppressing tumour progression, decreasing inflammation and influencing estrogen metabolism. These mechanisms may be mediated by changes in DNA methylation.To investigate if DNA methylation in blood is associated with coffee and tea consumption we performed a genome-wide DNA methylation study for coffee and tea consumption in four European cohorts (N = 3,096). DNA methylation was measured from whole blood at 421,695 CpG sites distributed throughout the genome and analysed in men and women both separately and together in each cohort. Meta-analyses of the results and additional regional-level analyses were performed.After adjusting for multiple testing, the meta-analysis revealed that two individual CpG-sites, mapping to DNAJC16 and TTC17, were differentially methylated in relation to tea consumption in women. No individual sites were associated in men or in the sex-combined analysis for tea or coffee. The regional analysis revealed that 28 regions were differentially methylated in relation to tea consumption in women. These regions contained genes known to interact with estradiol metabolism and cancer. No significant regions were found in the sex-combined and male-only analysis for either tea or coffee consumption.
|
|
| 2. |
- Hesselman, Susanne, 1973-, et al.
(author)
-
Time matters—a Swedish cohort study of labor duration and risk of uterine rupture
- 2021
-
In: Acta Obstetricia et Gynecologica Scandinavica. - : John Wiley & Sons. - 0001-6349 .- 1600-0412. ; 100:10, s. 1902-1909
-
Journal article (peer-reviewed)abstract
- IntroductionUterine rupture is an obstetric emergency associated with maternal and neonatal morbidity. The main risk factor is a prior cesarean section, with rupture occurring in subsequent labor. The aim of this study was to assess the risk of uterine rupture by labor duration and labor management.Material and methodsThis is a Swedish register-based cohort study of women who underwent labor in 2013–2018 after a primary cesarean section (n = 20 046). Duration of labor was the main exposure, calculated from onset of regular labor contractions and birth; both timepoints were retrieved from electronic medical records for 12 583 labors, 63% of the study population. Uterine rupture was calculated as events per 1000 births at different timepoints during labor. Risk estimates for uterine rupture by labor duration, induction of labor, use of oxytocin and epidural analgesia were calculated using Poisson regression, adjusted for maternal and birth characteristics. Estimates were presented as adjusted rate ratios (ARR) with 95% confidence intervals (CI).ResultsThe prevalence of uterine rupture was 1.4% (282/20 046 deliveries). Labor duration was 9.88 hours (95% CI 8.93–10.83) for women with uterine rupture, 8.20 hours (95% CI 8.10–8.31) for women with vaginal delivery, and 10.71 hours (95% CI 10.46–10.97) for women with cesarean section without uterine rupture. Few women (1.0/1000) experienced uterine rupture during the first 3 hours of labor. Uterine rupture occurred in 15.6/1000 births with labor duration over 12 hours. The highest risk for uterine rupture per hour compared with vaginal delivery was observed at 6 hours (ARR 1.20, 95% CI 1.11–1.30). Induction of labor was associated with uterine rupture (ARR 1.54, 95% CI 1.19–1.99), with a particular high risk seen in those induced with prostaglandins and no risk observed with cervical catheter (ARR 1.19, 95% CI 0.83–1.71). Labor augmentation with oxytocin (ARR 1.60, 95% CI 1.25–2.05) and epidural analgesia (ARR 1.63, 95% CI 1.27–2.10) were also associated with uterine rupture.ConclusionsLabor duration is an independent factor for uterine rupture among women attempting vaginal delivery after cesarean section. Medical induction and augmentation of labor increase the risk, regardless of maternal and birth characteristics.
|
|
| 3. |
- Lampa, Erik G., et al.
(author)
-
Optimizing occupational exposure measurement strategies when estimating the log-scale arithmetic mean value : An example from the reinforced plastics industry
- 2006
-
In: Annals of Occupational Hygiene. - Oxford : Pergamon Press. - 0003-4878 .- 1475-3162. ; 50:4, s. 371-377
-
Journal article (peer-reviewed)abstract
- When assessing occupational exposures, repeated measurements are in most cases required. Repeated measurements are more resource intensive than a single measurement, so careful planning of the measurement strategy is necessary to assure that resources are spent wisely. The optimal strategy depends on the objectives of the measurements. Here, two different models of random effects analysis of variance (ANOVA) are proposed for the optimization of measurement strategies by the minimization of the variance of the estimated log-transformed arithmetic mean value of a worker group, i.e. the strategies are optimized for precise estimation of that value. The first model is a one-way random effects ANOVA model. For that model it is shown that the best precision in the estimated mean value is always obtained by including as many workers as possible in the sample while restricting the number of replicates to two or at most three regardless of the size of the variance components. The second model introduces the ‘shared temporal variation’ which accounts for those random temporal fluctuations of the exposure that the workers have in common. It is shown for that model that the optimal sample allocation depends on the relative sizes of the between-worker component and the shared temporal component, so that if the between-worker component is larger than the shared temporal component more workers should be included in the sample and vice versa. The results are illustrated graphically with an example from the reinforced plastics industry. If there exists a shared temporal variation at a workplace, that variability needs to be accounted for in the sampling design and the more complex model is recommended.
|
|
| 4. |
- Törn, Anna E., et al.
(author)
-
Hypoxic ischemic encephalopathy in offspring of immigrant women in Sweden : A population-based cohort study
- 2021
-
In: Acta Obstetricia et Gynecologica Scandinavica. - : John Wiley & Sons. - 0001-6349 .- 1600-0412. ; 100:12, s. 2285-2293
-
Journal article (peer-reviewed)abstract
- Introduction One in four women giving birth in Sweden is foreign-born. Immigrant status has been suggested as a risk factor for adverse perinatal outcomes. It is not known if infants to foreign-born women have an increased risk of severe birth asphyxia, or which factors might mediate such association. Material and methods A population-based cohort study of 726 730 live births at 36 weeks of gestation or more in Sweden in 2009-2015. The exposure was maternal country of birth, grouped according to the World Bank country classification: low-, lower-middle, upper-middle, and high-income economies. The main outcome was neonatal hypoxic ischemic encephalopathy (HIE). The outcome was estimated by severity and classified as non-hypothermia-treated HIE, representing mainly mild cases, and hypothermia-treated HIE, representing moderate to severe cases. A secondary outcome was low Apgar score at 5 minutes, defined as <7 or <4. Odds ratios with 95% CI were calculated, using Swedish-born women as the reference. Structural equation modeling was used to investigate potential mediation of known antepartum risk factors. Results A total of 854 infants were diagnosed with HIE and 398 received therapeutic hypothermia. Offspring of mothers born in low-income countries had the highest incidences of HIE and low Apgar score, with an incidence of therapeutic hypothermia of 1.1 per 1000. Compared with offspring of Swedish-born mothers, these neonates had an almost two-fold increased risk of HIE, with or without hypothermia treatment (odds ratio 1.7; 95% CI 1.2-2.7 and odds ratio 1.7; 95% CI 1.2-2.6, respectively), and a 2- to 3-fold increased risk of low Apgar score. The structural equation model analysis indicated an exclusive direct effect of country of birth on HIE. Factors reflecting socio-economic status mediated a small proportion of the risk of Apgar score <7 at 5 minutes. Conclusions Offspring of women born in low-income countries had associations with severe birth asphyxia, with increased risk of both HIE and low Apgar score at 5 minutes. The associations seemed only to be marginally mediated by other antepartum factors. The associations are complex and further studies are needed to find explanatory and potentially preventable factors.
|
|
| 5. |
- Wang, Yunzhang, et al.
(author)
-
Epigenetic influences on aging : a longitudinal genome-wide methylation study in old Swedish twins
- 2018
-
In: Epigenetics. - : Informa UK Limited. - 1559-2294 .- 1559-2308. ; 13:9, s. 975-987
-
Journal article (peer-reviewed)abstract
- Age-related changes in DNA methylation were observed in cross-sectional studies, but longitudinal evidence is still limited. Here, we aimed to characterize longitudinal age-related methylation patterns using 1011 blood samples collected from 385 Swedish twins (age at entry: mean 69 and standard deviation 9.7, 73 monozygotic and 96 dizygotic pairs) up to five times (mean 2.6) over 20 years (mean 8.7). We identified 1316 age-associated methylation sites (P<1.3x10(-7)) using a longitudinal epigenome-wide association study design. We measured how estimated cellular compositions changed with age and how much they confounded the age effect. We validated the results in two independent longitudinal cohorts, where 118 CpGs were replicated in Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS, 390 samples) (P<3.9x10(-5)), 594 in Lothian Birth Cohort (LBC, 3018 samples) (P<5.1x10(-5)) and 63 in both. Functional annotation of age-associated CpGs showed enrichment in CCCTC-binding factor (CTCF) and other transcription factor binding sites. We further investigated genetic influences on methylation and found no interaction between age and genetic effects in the 1316 age-associated CpGs. Moreover, in the same CpGs, methylation differences within twin pairs increased with 6.4% over 10 years, where monozygotic twins had smaller intra-pair differences than dizygotic twins. In conclusion, we show that age-related methylation changes persist in a longitudinal perspective, and are fairly stable across cohorts. The changes are under genetic influence, although this effect is independent of age. Moreover, methylation variability increase over time, especially in age-associated CpGs, indicating the increase of environmental contributions on DNA methylation with age.
|
|
