Effects of caffeine on human health

Caffeine is probably the most frequently ingested pharmacologically active substance in the world. It is found in common beverages (coffee, tea, soft drinks), in products containing cocoa or chocolate, and in medications. Because of its wide consumption at different levels by most segments of the population, the public and the scientific community have expressed interest in the potential for caffeine to produce adverse effects on human health. The possibility that caffeine ingestion adversely affects human health was investigated based on reviews of (primarily) published human studies obtained through a comprehensive literature search. Based on the data reviewed, it is concluded that for the healthy adult population, moderate daily caffeine intake at a dose level up to 400 mg day^-1 (equivalent to 6 mg kg^-1 body weight day^-1 in a 65-kg person) is not associated with adverse effects such as general toxicity, cardiovascular effects, effects on bone status and calcium balance (with consumption of adequate calcium), changes in adult behaviour, increased incidence of cancer and effects on male fertility. The data also show that reproductive-aged women and children are 'at risk' subgroups who may require specific advice on moderating their caffeine intake. Based on available evidence, it is suggested that reproductive-aged women should consume ≤ 300 mg caffeine per day (equivalent to 4.6 mg kg^-1 bw day^-1 for a 65-kg person) while children should consume ≤ 2.5 mg kg^-1 bw day^-1.     

Pregnant women in vehicles: Driving habits,position and risk of injury

This study proposed to broadly examine vehicle use by pregnant women in order to improve realism of accident simulations involving these particular occupants. Three research pathways were developed: the first consisted in a questionnaire survey examining the driving habits of 135 pregnant women, the second obtained measurements of 15 pregnant women driving position in their own vehicle from the 6th to the 9th month of pregnancy by measuring distances between body parts and vehicle parts, and the third examined car accidents involving pregnant occupants. Results obtained indicate that between 90% and 100% of pregnant women wore their seat belts whatever their stage of pregnancy, although nearly one third of subjects considered the seat belt was dangerous for their unborn child. The measurements obtained also showed that the position of the pregnant woman in her vehicle, in relation to the various elements of the passenger compartment, changed significantly during pregnancy. In the studied accidents, no correlation was found between the conditions of the accident and the resulting fetal injury. Results reveal that pregnant women do not modify significantly the seat setting as a function of pregnancy stage. Only the distance between maternal abdomen and steering wheel change significantly, from 16 cm to 12 cm at 6 and 9 month respectively. Pregnant women are mainly drivers before 8 months of pregnancy, passengers after that. Car use frequency falls down rapidly from 6 to 9 months of pregnancy. Real crashes investigations indicate a low rate of casualties, i.e. 342 car accidents involving pregnant women for a period of 9 years in an approximately 1.7 million inhabitants area. No specific injury was found as a function of stage of pregnancy.     

“妊娠生理”多媒体CAI课件设计与开发

妊娠生理是高职护理与助产专业妇产学科的教学重难点,静态的文字图片难以表达出临床中的这一生理现象。文章介绍了利用Authorware7.0等软件开发了《妊娠生理》多媒体课件的实现过程,就课件的设计思想、课件的结构以及关键的制作技术进行了阐述和研究。课件将复杂的生理过程通过交互的动画方式直观化,不易察觉的变化过程清楚地展现在学生面前,有效提高了教学质量与学习效率。     

钙,微量元素与妊娠关系的初步研究

用X射线荧光分析法(XRF)测定了1023例孕妇发中的Ca以及9种微量元素含量,与270例对照组相比,孕妇发中Sr、Mn、Ca含量显著降低(p<0.01),Zn、Cu、Fe含量也有不同程度的降低,特别是在妊娠晚期。     

Longitudinal Assessment of Erythrocyte Fatty Acid Composition Throughout Pregnancy and Post Partum

Transfer of fatty acids from mother to fetus during pregnancy is a requirement for optimal fetal growth. We report a longitudinal study of full maternal erythrocyte fatty acid profile assessed at each trimester of pregnancy [mean 12.5 (range 8–14), 26.1 (24–28) and 35.5 (33–38) weeks’ gestation] and in the post partum period [18.1 (12–26) weeks]. The study recruited healthy women (n = 47) from routine antenatal clinics at the Princess Royal Maternity Unit, Glasgow, Scotland. There were increases in 16:1n7 (22%, p = 0.0005), 24:1n9 (13%, p = 0.0032), 22:5n6 (25%, p = 0.0003), 18:3n3 (41%, p = 0.0007) and 22:6n3 (20%, p = 0.0005) concentrations during pregnancy. The greatest increases took place between gestations at sampling of 12.5 and 26.1 weeks. The change in 16:1n7 concentration between gestations at sampling of 12.5 and 35.3 weeks was negatively associated with maternal booking body mass index (r = −0.40, p = 0.006). The change in 22:6n3 concentration was correlated with the change in 24:1n9 (r = 0.70, p < 0.001). In samples taken four months post partum, 14:0 concentration was lower (29%, p = 0.0002) and 24:0 concentration (15%, p = 0.0009) and n6/n3 ratio (11%, p = 0.0019) were higher than at a gestation at sampling of 12.5 weeks. In conclusion, several fatty acids are specifically mobilised during pregnancy. The correlation between maternal 22:6n3 and 24:1n9 suggests that mobilisation of these fatty acids may be coordinated. The inverse relationship between 16:1n7 and maternal central obesity warrants further investigation.     

Genetic Risk Scores for Maternal Lipid Levels and Their Association with Preterm Birth

Maternal lipid profiles are associated with risk for preterm birth (PTB), although the lipid component and effect size are inconsistent between studies. It is also unclear whether these associations are the result of excessive changes in lipid metabolism during pregnancy or genetic variability in genes controlling basal lipid metabolism. This study investigates the association between genetic risk scores (GRS) for four lipid components (high-density lipoprotein [HDL-C], low-density lipoprotein [LDL-C], triacylglycerols [TAG], and total cholesterol [TC]) with risk for PTB. Subjects included 954 pregnant women from California for whom second trimester serum samples were available, of which 479 gave birth preterm and 475 gave birth at term. We genotyped 96 single-nucleotide polymorphisms, which were selected from genome-wide association studies of lipid levels in adult populations. Lipid-specific GRS were constructed for HDL-C, LDL-C, TAG, and TC. The associations between GRS and PTB were analyzed using logistic regression. A higher HDL-C GRS was associated with increased risk for PTB overall and spontaneous PTB. Higher TAG and TC GRS were associated with decreased risk for PTB overall and spontaneous PTB. This study identifies counter-intuitive associations between lipid GRS and spontaneous PTB. Further replication studies are needed to confirm these findings, but they suggest that our current scientific understanding of the relationship between lipid metabolism, PTB, and genetics is incomplete.     

Effect of prenatal exposure to fine particulate matter and intake of Paracetamol (Acetaminophen) in pregnancy on eczema occurrence in early childhood

The goal of the study was to test the hypothesis that prenatal Paracetamol exposure increases the risk of developing eczema in early childhood and that this association may be stronger in children who are exposed in fetal period to higher concentrations of fine particulate matter (PM_2.5). The study sample consisted of 322 women recruited from January 2001 to February 2004 in the Krakow inner city area who gave birth to term babies and completed 5-year follow-up. Paracetamol use in pregnancy was collected by interviews and prenatal personal exposure to PM_2.5 over 48 h was measured in recruited women in the second trimester of pregnancy. After delivery, every three months in the first 24 months of the newborn's life and every 6 months later, a detailed standardized face-to-face interview on the infant's health was administered to each mother by trained interviewers. During the interviews at each of the study periods after birth, a history of eczema was recorded.The incident rate ratio (IRR) for frequency of eczema events over the follow-up was estimated from the Poisson regression model and the overall effect of main exposure variables on eczema was assessed by odds ratios (ORs) by the logistic model. The estimated relative risk of eczema occurring whenever in the follow-up was related significantly neither with prenatal Paracetamol nor higher PM_2.5 exposure, however, their joint effect was significant (OR interaction term = 6.04; 95%CI: 1.04-35.16). Of potential confounders considered in the analysis only damp/moldy home significantly increased the risk of eczema (OR = 1.53; 95%CI: 1.14-2.05). In contrast, there was an inverse significant association between the presence of older siblings and eczema (OR = 0.55; 95%CI: 0.35-0.84). The joint effect of the main exposure variables significantly increased frequency of eczema events (IRR = 1.78, 95%CI: 1.22-2.61).In conclusion, the findings of the study suggest that Paracetamol use by mothers in pregnancy is not an independent risk factor for eczema in children, however, even very small doses of Paracetamol taken in pregnancy may contribute to the occurrence of allergic symptoms in early childhood if there is prenatal co-exposure to higher airborne fine particulate matter.