One in every 20 cases of the serious condition of pregnancy, pre-eclampsia, may be linked to increased levels of the air pollutant ozone during the first three months, suggests a large study published in the online journal BMJ Open.
Mothers with asthma may be more vulnerable, the findings indicate.
Pre-eclampsia is characterized by raised blood pressure and the presence of protein in the urine during pregnancy. It can cause serious complications, if left untreated.
The authors base their findings on almost 121,000 singleton births in Greater Stockholm, Sweden, between 1998 and 2006; national data on the prevalence of asthma among the children’s mothers; and levels of the air pollutants ozone and vehicle exhaust (nitrogen oxide) in the Stockholm area.
There’s a growing body of evidence pointing to a link between air pollution and premature birth, say the authors, while pregnant women with asthma are more likely to have pregnancy complications, including underweight babies and pre-eclampsia.
In all, 4.4 percent of the pregnancies resulted in a premature birth and the prevalence of pre-eclampsia was 2.7 percent.
There was no association between exposure to levels of vehicle exhaust and complications of pregnancy, nor were any associations found for any air pollutants and babies that were underweight at birth.
But there did seem to be a link between exposure to ozone levels during the first three months of pregnancy and the risk of premature birth (delivery before 37 weeks) and pre-eclampsia, after adjusting for factors likely to influence the results and seasonal variations in air pollutants, although not spatial variations in exposure.
Each rose by 4 percent for every 10 ug/m3 rise in ambient ozone during this period, the analysis indicated.
Mothers with asthma were 25 percent more likely to have a child born prematurely and 10 percent more likely to have pre-eclampsia than mums without this condition.
Asthma is an inflammatory condition and ozone may therefore have worsened respiratory symptoms and systemic inflammation, so accounting for the larger increase in the risk of premature birth among the mums with asthma, suggest the authors.
But after taking account of the mother’s age, previous births, educational attainment, ethnicity, asthma, season and year of conception, the authors calculated that one in every 20 (5%) cases of pre-eclampsia were linked to ozone levels during early pregnancy.
A newly identified genetic variant doubles the risk of calcium buildup in the heart’s aortic valve. Calcium buildup is the most common cause of aortic stenosis, a narrowing of the aortic valve that can lead to heart failure, stroke, and sudden cardiac death.
An international genomics team called CHARGE (Cohorts for Heart and Aging Research in Genomic Epidemiology) found the variant in the gene for lipoprotein(a), a cholesterol-rich particle that circulates in the blood.
CHARGE oversees genomic studies of five large study populations in the United States and Europe, including the Framingham Heart Study (FHS), which is a part of the National Heart, Lung, and Blood Institute (NHLBI) at the National Institutes of Health.
The findings will be published in the Feb. 7 issue of The New England Journal of Medicine.
“No medications tested to date have shown an ability to prevent or even slow progression of aortic stenosis, and treatments are limited beyond the major step of replacing the aortic valve,” said study co-author Christopher O’Donnell, M.D., M.P.H., senior director for genome research at the NHLBI and associate director of the FHS. “By identifying for the first time a common genetic link to aortic stenosis, we might be able to open up new therapeutic options.”
The CHARGE researchers conducted a genome-wide analysis of 2.5 million known genetic variants in a group of nearly 7,000 white participants. The analysis identified a variant in the lipoprotein(a), or Lp(a), gene that was highly correlated with calcification of the aortic valve, as measured by computed tomography (CT) scanning.
Followup analysis in more than 6,000 additional participants, including Hispanics, African-Americans, and Chinese-Americans, confirmed this correlation.
The variant was present in about 7 percent of the study population and the people who carry it generally had higher amounts of Lp(a) circulating in their blood. The function of Lp(a) is unknown, but it is associated with an elevated risk of heart disease.
Another independent analysis carried out by CHARGE followed participants in Sweden and Denmark, and found that people with the Lp(a) variant had higher risks of clinical heart valve disease and of needing valve replacement surgery.
“What makes these findings provocative is that we linked the genetic variant with a physiological change in lipoprotein levels, disease precursor in the form of calcium buildup, and fully diagnosed aortic valve disease, across multiple ethnicities,” O’Donnell said. “The study suggests a causal relation between Lp(a) and aortic valve disease, but further work will be needed to see whether medications that lower Lp(a) levels can lower the risk or slow the development of valve disease.”
In addition to the FHS, this work included data from the NHLBI’s Multi-Ethnic Study of Atherosclerosis, the Age Gene/Environment Susceptibility Study, the Heinz Nixdorf Recall Study, the Malmo Diet and Cancer Study, and the Copenhagen City Heart Study.
Physicians often fail to ask high school-aged patients about alcohol use and to advise young people to reduce or stop drinking, according to a study led by the National Institute on Alcohol Abuse and Alcoholism (NIAAA), part of the National Institutes of Health.
In a random survey of more than 2,500 10th grade students with an average age of 16 years, researchers from NIAAA and the Eunice Kennedy Shriver National Institute of Child Health and Human Development found that 34 percent reported drinking alcohol in the past month.
Twenty-six percent said they had binged, defined as five or more drinks per occasion for males, and four or more for females.
“While more than 80 percent of 10th graders said they had seen a doctor in the past year, just 54 percent of that group were asked about drinking, and 40 percent were advised about alcohol harms,” said lead author Ralph W. Hingson, Sc.D., M.P.H., director of NIAAA’s division of epidemiology and prevention research.
He added that, among students who had been seen by a doctor in the past year and who reported drinking in the past month, only 23 percent said they were advised to reduce or stop drinking. The findings are now online in the February issue of Pediatrics.
The researchers also reported that students who said that they had been asked about their drinking were more likely to be advised about alcohol.
Nevertheless, among the 43 students who said that they were drunk six times or more in the past month and who said they had been asked about their drinking by a doctor, about 30 percent were not advised about drinking risks, and two-thirds were not advised to reduce or stop drinking.
The researchers caution that in the survey students were asked about past-month drinking, not what they may have told their physicians about their drinking.
Studies have shown that screening and brief interventions by health care providers – asking patients about alcohol use and advising them to reduce risky drinking – can promote significant, lasting reductions in drinking levels and alcohol-related problems among adults.
Accumulating evidence supports the use of alcohol screening among adolescents.
In 2011, NIAAA and the American Academy of Pediatrics released a two-question screening tool designed to help clinicians overcome time constraints and other common barriers to youth alcohol screening. Examples of these questions, which vary slightly for elementary, middle, and high school ages, include:
“Do you have any friends who drank beer, wine, or any drink containing alcohol in the past year?”
“How about you – in the past year, on how many days have you had more than a few sips of beer, wine, or any drink containing alcohol?”
“Alcohol is by far the drug of choice among youth,” said NIAAA acting director Kenneth R. Warren, Ph.D. “The findings reported by Dr. Hingson and his colleagues indicate that we must redouble our efforts to help clinicians make alcohol screening a routine part of patient care for young people in the United States.”
Obesity can lead to a lack of vitamin D circulating in the body, according to a study led by the UCL Institute of Child Health (ICH).
Efforts to tackle obesity should thus also help to reduce levels of vitamin D deficiency in the population, says the lead investigator of the study, Dr Elina Hypponen.
While previous studies have linked vitamin D deficiency with obesity, the ICH-led paper, published in the journal PLOS Medicine, sought to establish the direction of causality, i.e., whether a lack of vitamin D triggers a weight gain, or whether obesity leads to the deficiency.
This study, based on an ICH-led D-CarDia Collaboration, used genetic markers derived from an analysis of 21 adult cohort groups (up to 42,000 participants) to explore the link between body mass index (BMI) and genes associated with the synthesis and metabolism of vitamin D.
Associations between vitamin D and BMI were further confirmed using data from another genetic consortium with over 123,000 participants.
Researchers found that a 10 percent rise in BMI was linked to a four percent drop in concentrations of vitamin D in the body.
Overall, the findings suggest that a higher BMI leads to lower levels of available vitamin D, while the effect of a lack of vitamin D on BMI appears to be very small.
The association between obesity and vitamin D status found here was consistent between genders, being apparent both in men and in women, and in younger and older age groups.
Vitamin D, which is essential for healthy bones as well as other functions, is made in the skin after exposure to sunlight but can also be obtained through the diet and through supplements.
Obesity and vitamin D status are known to be associated, but the direction of the association and whether it is causal has been uncertain up to now.
Vitamin D deficiency is a growing public health concern, and there is evidence that vitamin D metabolism, storage and action both influence and are influenced by adiposity or body fat.
While experiments in rats have suggested that large doses of vitamin D2 can boost the amount of energy they burn, trials testing the effect of vitamin D supplements on weight loss in obese or overweight people have not shown any consistent findings.
It has also been suggested that obesity could result from an excessive adaptive winter response, and that the decline in vitamin D skin synthesis from less exposure to sunlight contributes to the tendency to put on weight during colder seasons.
However, vitamin D is stored in fatty tissue and thus, the most likely explanation for the association found in the ICH-led study is that the larger storage capacity for vitamin D in obese people leads to lower circulating concentrations of vitamin D.
Overall, the ICH results suggest that although increases in vitamin D are not likely to help with weight regulation, increased risk of vitamin D deficiency could contribute to the adverse health effects associated with obesity.
Dr. Elina Hypponen, UCL Institute of Child Health and lead author of the study, said: “Vitamin D deficiency is an active health concern around the world. While many health messages have focused on a lack of sun exposure or excessive use of suncreams, we should not forget that vitamin D deficiency is also caused by obesity.”
She added, “Our study highlights the importance of monitoring and treating vitamin D deficiency in people who are overweight or obese, in order to alleviate adverse health effects caused by a lack of vitamin D.”