Risk of miscarriage linked strongly to mother’s age and pregnancy history

Externally peer-reviewed? Yes
Type of evidence: Observational
Subjects: Women

Findings point to new insights into possible shared underlying causes of miscarriage

Miscarriage (Image source: Pixabay)
Miscarriage (Image source: Pixabay)

The risk of miscarriage varies greatly with a woman’s age, shows a strong pattern of recurrence, and is increased after some pregnancy complications, finds a study from Norway published in The BMJ today.

The findings suggest that miscarriage and other pregnancy complications might share underlying causes, which warrant further study, say the researchers.
Miscarriage is a common pregnancy outcome, but the risk is challenging to estimate because of inconsistent recording. Norway is one of the few countries where miscarriage data has been consistently collected since 2008.

So a team of researchers, led by Maria Magnus at the Norwegian Institute of Public Health, set out to estimate the risk of miscarriage among Norwegian women and to evaluate the association with age and pregnancy history.

They used Norwegian health registers (medical birth register, patient register, and the induced abortion register) to identify all pregnancies in Norway between 2009 and 2013.

Risk of miscarriage was estimated according to the woman’s age and pregnancy history, taking into account induced abortions.

There were 421,201 pregnancies during the study period. After accounting for induced abortions, the overall miscarriage rate was 12.8%. The risk of miscarriage was lowest among women aged 25-29 (10%), and rose rapidly after age 30, reaching 53% among women age 45 years and over.

There was also a strong recurrence risk of miscarriage. After one miscarriage, the risk of another was increased by half, after two, the risk doubled, and after three consecutive miscarriages, the risk was four times greater.

Previous pregnancy complications also predicted a higher risk of miscarriage. For example, if the previous birth ended in a preterm delivery, caesarean section, or if the woman had diabetes during pregnancy (gestational diabetes). However, pre-eclampsia (abnormally high blood pressure) in the previous pregnancy was not associated with increased risk of miscarriage.

Women who themselves were born small also had an increased risk of miscarriage.

This is an observational study, and as such, can’t establish cause, and the researchers point to some limitations, such as the possibility that early miscarriages which did not result in contact with specialist health-care services were not captured.

Nevertheless, they say their results provide more precise estimates of the risk of miscarriage related to a mother’s age and suggest that the risk of miscarriage is linked to some previous pregnancy complications.

“More focused studies of these associations might lead to new insights regarding the shared underlying causes of pregnancy complications and miscarriage,” they conclude.

Notes:
Research: Role of maternal age and pregnancy history in risk of miscarriage: prospective register based study
Journal: The BMJ

http://www.bmj.com/content/364/bmj.l869

Author contact:
Maria C Magnus, Researcher, Centre for Fertility and Health, Norwegian Institute of Public Health, Oslo, Norway
Tel: +47 99 160 012
Email: Maria.Christine.Magnus@fhi.no

Data sharing by popular health apps is routine and far from transparent, warn experts

Externally peer-reviewed? Yes
Type of evidence: Traffic and network analysis
Subjects: Mobile apps

Developers should allow users to choose precisely what data are shared and with whom, say researchers

Health-related apps (Image source: Pixabay)
Health-related apps (Image source: Pixabay)

Sharing of user data by popular mobile health applications (apps) is routine, yet far from transparent, warn experts in a study published in The BMJ today.

They say regulators should emphasise the accountabilities of those who control and process user data, and health app developers should disclose all data sharing practices and allow users to choose precisely what data are shared and with whom.

App developers routinely, and legally, share user data. But evidence suggests that many health apps fail to provide privacy assurances around data sharing practices, and pose unprecedented risk to consumers’ privacy, given their ability to collect sensitive and personal health information.

So researchers led by Assistant Professor Quinn Grundy at the University of Toronto, set out to investigate whether and how user data are shared by popular medicines related mobile apps and to characterise privacy risks to app users, both clinicians and consumers.

They identified 24 top rated medicines related apps for the Android mobile platform in the United Kingdom, United States, Canada, and Australia.

All apps were available to the public, provided information about medicines dispensing, administration, prescribing, or use, and were interactive.

First, they downloaded each app onto a smartphone and used four dummy user profiles to simulate real world use.

They ran each app 14 times and found baseline traffic relating to 28 different types of user data. They then altered one source of user information and ran the app again to detect any privacy leaks (sensitive information sent to a remote server, outside of the app). Companies receiving sensitive user data were then identified by their IP address, and their websites and privacy policies were analysed.

Most (19 out of 24; 79%) of the sampled apps shared user data outside of the app.

A total of 55 unique entities, owned by 46 parent companies, received or processed app user data, including developers and parent companies (first parties) and service providers (third parties).

Of these, 18 (33%) provided infrastructure related services such as cloud services and 37 (67%) provided services related to the collection and analysis of user data, including analytics or advertising, suggesting heightened privacy risks.

Network analysis revealed that first and third parties received an average of three unique transmissions of user data. Both Amazon.com and Alphabet (the parent company of Google) received the highest volume of user data (24 unique transmissions), followed by Microsoft (14).

Third parties also advertised the ability to share user data with 216 “fourth parties” including multinational technology companies, digital advertising companies, telecommunications corporations, and a consumer credit reporting agency.

Only three of these fourth parties could be characterised predominantly as belonging to the health sector.

Several companies, including Alphabet, Facebook, and Oracle, occupied central positions within the network with the ability to aggregate and re-identify user data

The researchers point to some limitations that may have influenced the results. For example, it is unknown whether iOS apps share user data and whether these apps share user data more or less than other health apps, or apps in general.

Nevertheless, they say their findings suggest that health professionals “should be conscious of privacy risks in their own use of apps and, when recommending apps, explain the potential for loss of privacy as part of informed consent.”

Privacy regulators should also consider that loss of privacy is not a fair cost for the use of digital health services, they conclude.

Notes:
Research: Data sharing practices of medicines related apps and the mobile ecosystem: traffic, content, and network analysis
Journal: The BMJ

http://www.bmj.com/content/364/bmj.l920

Author contacts:
Quinn Grundy, Assistant professor and honorary senior lecturer, Faculty of Nursing, University of Toronto, Toronto, ON, Canada
Tel: +1 647 913 7075
Email: quinn.grundy@utoronto.ca (or @quinngrundy on Twitter

Dr Ralph Holz, School of Computer Science, The University of Sydney, Sydney, NSW, Australia
Tel: +61 475 421 044
Email: ralph.holz@sydney.edu.au

Early life exposure to common pesticides linked to small increased risk of autism spectrum disorder

Externally peer-reviewed? Yes (research); No (editorial)
Type of evidence: Observational; Opinion
Subjects: Offspring
Findings support efforts to prevent exposure to pesticides during pregnancy

Autism thinking (Image source: Pixabay)
Autism thinking (Image source: Pixabay)

Exposure to common agricultural pesticides before birth and in the first year of life is associated with a small to moderately increased risk of autism spectrum disorder (ASD) compared with infants of women without such exposure, finds a study published in The BMJ today.

The researchers say their findings support efforts to prevent exposure to pesticides during pregnancy to protect a child’s developing brain.

Experimental studies have suggested that common pesticides can affect normal brain development, and environmental exposures during early brain development are suspected to increase risk for autism spectrum disorders in children.

But studies examining pesticide exposure in the real world and risk of ASD are rare.

So researchers at the University of California used registry records to identify 2,961 patients with a diagnosis of ASD – including 445 with ASD with accompanying intellectual disability – and 35,370 healthy (“control”) patients of the same birth year and sex.

Participants were born between 1998 and 2010 in California’s Central Valley, a heavily agricultural region, and 80% of cases were male.

Data from the California state-mandated Pesticide Use Registry were then integrated into a geographic information system tool to assess prenatal (before birth) and infant exposures to 11 commonly used pesticides (measured as pounds of pesticides applied per acre/month within 2 km of their mother’s residence during pregnancy and exposure during developmental periods defined as yes vs no).

These pesticides were selected because of their high use and evidence indicating toxic effects on brain development.

After adjusting for potentially influential factors, the researchers found modest increases in ASD risk among offspring exposed to several pesticides (including glyphosate, chlorpyrifos, diazinon, malathion,  permethrin, bifenthrin and methyl-bromide) before birth and during the first year of life, compared with controls.

Associations were strongest in those with ASD and intellectual disability, which represents the more severe end of the autism spectrum.

This is an observational study, and as such, can’t establish cause, and the researchers point to some limitations, such as relying on patient records for details about diagnoses, and being unable to examine clinical outcomes.

Nevertheless, they say their study is by far the largest investigating pesticides and autism spectrum disorder to date and their findings back up earlier work in this field.

“Our findings suggest that ASD risk may increase with prenatal and infant exposure to several common ambient pesticides that impacted neurodevelopment in experimental studies,” they write.

They call for further research to explore underlying mechanisms in the development of autism. However, from a public health and preventive medicine perspective, they say their findings “support the need to avoid prenatal and infant exposure to pesticides to protect the developing child’s brain.”

In a linked editorial, Amanda Bakian and James VanDerSlice at the University of Utah agree that reducing exposure to pesticides during pregnancy “is sensible public health policy” but they point out that this “might be close to impossible for some populations.”

Future research exploring underlying biological mechanisms and individual susceptibilities in other regions of the world “may help to translate these study findings into more refined public health actions for pregnant women residing in areas of high pesticide use,” they conclude.


Notes:
Research: Prenatal and infant exposure to ambient pesticides and autism spectrum disorder in children: population based case-control study
Editorial: Pesticides and autism
Journal: The BMJ

http://www.bmj.com/content/364/bmj.l962

Author contacts:

Research: Dr Ondine von Ehrenstein, Associate Professor, Departments of Community Health Science and Epidemiology, Fielding School of Public Health, University of California, Los Angeles, CA, USA
Tel: +1 213 298 70 24
Email: ovehren@ucla.edu

Editorial: Amanda Bakian, Assistant Professor, Division of Child and Adolescent Psychiatry, Department of Psychiatry, University of Utah, Salt Lake City, UT, USA
Tel: +1 801 581 5413
Email: amanda.bakian@hsc.utah.edu

New Labour’s policies reduced geographical inequalities in infant mortality rates

Teddy bear

Externally peer reviewed? Yes
Evidence type: Observational
Subjects: People
The gap in infant mortality rates between English local authorities narrowed between 1999-2010, but that trend has been reversed since 2011 – perhaps as a result of austerity.

Efforts by the Labour government to reduce inequalities between the most deprived areas of England and the rest of the country had a positive impact on infant mortality rates, suggests research by the Universities of Newcastle, Leeds, York, and Liverpool published online in the Journal of Epidemiology & Community Health.

However, the authors warn that the current Conservative government’s austerity policies may have undermined these gains because the trend in decreasing inequalities has not continued perhaps due to austerity measures.

When Tony Blair’s New Labour government came to power in 1997, it attempted to use policy levers to reduce geographical health inequalities in England.

There was a focus on early years, education, supporting families, engaging communities in tackling deprivation, improving prevention, increasing access to healthcare and tackling the underlying social determinants of health (e.g. via tax credits and introducing the minimum wage).

A range of social programmes such as SureStart were funded and there were large funding increases for the NHS and other public services.

However, when the Conservative–Liberal Democrat coalition took control in 2010 this strategy was replaced with austerity measures intended to reduce the national deficit.

For this study the authors examined what impact New Labour’s policies had on health inequalities by measuring inequalities in the infant mortality rate between the most deprived local authorities and the rest of England before, during and after its health inequalities strategy was put in place.

They found that before New Labour’s health inequalities strategy (1983–1998), the gap in the infant mortality between the most deprived local authorities and the rest of England increased at a rate of 3 infant deaths per 100,000 births per year.

During the strategy period (1999–2010), the gap narrowed by 12 infant deaths per 100,000 births per year and after the strategy period ended (2011–2017) the gap began increasing again at a rate of 4 deaths per 100,000 births per year.

There was also a marginal decrease in relative inequalities* during the strategy period.

This is an observational study, and as such, can’t establish causality. The authors also highlight that their results may have differed if they had used infant survival rather than infant mortality as an outcome measure, or occupational class rather than geographical area as a measure of deprivation.

The observed decrease in inequalities in the infant mortality rate may also have been impacted by broader government strategies rather than the health inequalities strategy alone, they add.

Nevertheless, they say: “The multifaceted English health inequalities strategy, implemented between 1999 and 2010, was associated with a decrease in geographical inequalities in the infant mortality rate between the most and less deprived English local authorities.”

“These results imply that government policies specifically introduced to decrease inequalities in health may be beneficial, and that their discontinuation as a result of austerity may see inequalities increasing again.”

They add that the findings have important implications for current and future health policy. “Our analysis suggests that it is increases in public spending on healthcare and welfare that are associated with decreases in inequalities in the infant mortality rate, and this is something that should be learnt from by current and future governments.

“Current government policies are arguably going in the wrong direction and may squander some of the gains made in the health inequalities strategy period,” they conclude.

Notes
*Relative inequality is the difference between the rate in the most deprived areas and the rate in the rest of England expressed as a proportion of the rate in the rest of England

Research: The impact of New Labour’s English health inequalities strategy on geographical inequalities in infant mortality: a time-trend analysis doi:10.1136/jech-2018-211679
Journal: Journal of Epidemiology & Community Health
http://jech.bmj.com/lookup/doi/10.1136/jech-2018-211679

Author contact:
Professor Clare Bambra, Newcastle University Institute for Health and Society, Newcastle upon Tyne, UK
Tel: +44 (0)191 208 8289
Email: clare.bambra@ncl.ac.uk

Even low levels of leisure time physical activity lowers risk of death

Physical activity (Image source: Pixabay)
Physical activity (Image source: Pixabay)

Externally peer reviewed? Yes
Evidence type: Observational; survey data
Subjects: People

And being active for longer or participating in vigorous sports has additional health benefits

Even low-level physical activities, such as walking or gardening, are associated with a lower risk of death from cardiovascular disease, cancer or any cause finds a large observational study published online in the British Journal of Sports Medicine.

Higher amounts of activity or more vigorous activities, such as running, cycling and competitive sports, are associated with additional health benefits that are not outweighed by the risks of participating in these activities, the authors say.

Every year, a representative sample of the US population is asked about their health and lifestyle behaviours for the National Health Interview Surveys. The authors used data collected through the surveys between 1997 and 2008 to estimate the activity levels of 88,140 people aged 40–85 years, and linked that data with registered deaths up until 31 December 2011.

They calculated the total leisure time physical activity of participants using definitions in 2008 US guidelines, which roughly equate one minute of vigorous activity such as running, fast cycling or competitive sports as equivalent to two minutes of moderate-intensity activity, such as brisk walking, gardening or dancing. Only activities lasting at least 10 continuous minutes were taken into account.

Compared with individuals who were inactive, those who participated in just 10–59 min/week of moderate physical activities during their leisure time had an 18% lower risk of death from any cause over the study period, and the health benefits continued to mount as activity levels went up.

US 2008 guidelines recommend at least 150 minutes per week of moderate activity done in at least 10 minute bouts, and individuals who participated in 150–299 min/week reduced their overall risk of death by 31%. Those who clocked up ten times this amount – 1500 min or more per week – almost halved their risk (46% lower).

Reductions in risk of death from cancer also corresponded with increasing activity levels.

In terms of risk of death from cardiovascular events such as strokes and heart attacks, individuals who were active for 10-59 min/week during their leisure time saw their risk fall by 12%, and those who did 120-299 min/week by 37%, compared with people who were inactive.

However, much greater levels of physical activity were not associated with any greater benefits; individuals who were active for 1500 min or more per week had a reduced risk of death from cardiovascular disease of 33% – so their risk of death was slightly higher than those who met recommended activity levels but undertaking more moderate amounts.

This is an observational study, and as such, can’t establish cause, and also relied on participants self-reporting activity levels. However, the authors point out that the study also has many strengths, including its large sample size representative of the US population, and that their findings support US recommendations on activity levels.

The study also showed that individuals who participated in vigorous physical activities had significantly lower risk of death than those who only did light/moderate physical activity, so the authors recommend, like the US guidelines, that people short of time should consider more vigorous activities.

Attaining the highest levels of physical activity assessed – 1500 min or more/week “is difficult to achieve for a working adult”, they admit. “Participation in vigorous-intensity activity is more time-efficient than moderate-intensity activity,” the authors say.

“Vigorous-intensity physical activity may be an attractive option for able-bodied individuals with limited time.”

Research: Beneficial associations of low and large doses of leisure time physical activity with all-cause, cardiovascular disease and cancer mortality: a national cohort study of 88,140 US adults doi:10.1136/bjsports-2018-099254
Journal: British Journal of Sports Medicine

http://bjsm.bmj.com/lookup/doi/10.1136/bjsports-2018-099254

Author contact:
Dr Bo Xi, Department of Epidemiology, School of Public Health, Shandong University, China
Email (preferred – author will respond promptly): xibo2007@126.com