The Week UK – 23 August 2019

Health &Science NEWS 19

24 August 2019 THE WEEK

What the scientists are saying...

Asnack-laden commute
People whose commutes take
them near fast-food restaurants
haveagreater-than-average
tendency to pile on the pounds,
research suggests. Prof Adriana
Dornelles,astatistician at
Arizona State University,
analysed food outlets along the
work journeys of 710 female
employees at 22 schools in New
Orleans. Those who drove past
the most fast-food joints tended
to haveahigher body mass
index (BMI)–and this remained
true even when other potentially
influential factors, such as
income and race, were taken
into account. Dornelles thinks
it is probable that tired
commutersare more likely to be tempted bythe
offerings of convenience food outlets if they are
easily accessible. “Afteralong day at work, the
last thing you are going to think about is [going]
home and [preparing]ameal,” she said.

Chlamydia vaccineareal prospect
The first ever clinical trial forachlamydia
vaccine has produced positive results–raising
hopes that it could provide an effective defence
against the world’s most common bacterial
sexually transmitted disease. In the randomised
controlled trial, the new vaccine–developed by
scientists at Imperial College London and the
Statens Serum Institut (SSI) in Denmark–was
tested on 30 chlamydia-free women, while
another five were givenaplacebo. None of the
women suffered adverse affects, and the vaccine
boosted levels of antibodies in their blood and
vaginal fluids–suggesting it had produced the
desired-for immune response. (Further, larger
trials will be needed to confirm this.) “We see
the antibodies asafirst line of defence,” said the
SSI’s Frank Follmann, co-author of the study
published in The Lancet. “They should be able
to target the bacteria once it enters the genital
tract.” Untreated chlamydia can cause infertility
and increases the risk of HIV. Although it can be
treated with antibiotics, the infection is often

symptomless to begin with,

so many people don’t realise

they have it. There were

almost 220,000 new cases in

England last year, and about

131 million are diagnosed

annually worldwide.

Why old tunes are best

It’s not just pop songs that

aren’t as good as they once

were, says The Times:astudy

has suggested that as bird

populations decline, their music-

making abilities deteriorate too.

Researchers from the University

of Hawaii conducteda40-year-

analysis of the songs of three

species of honeycreeper: small,

nectar-feeding birds found on

the Hawaiian island of Kauai. Over this period,

the populations of all three species fell

precipitously–chiefly asaresult of avian

malaria,aparasite that spreads more extensively

as temperatures rise. And this appeared to have

hadadisastrous impact on the birds’ songs,

which became markedly less complex and more

uniform. “With population declines there are

fewer adults for young birds to learn from,”

explained Kristina Paxton, who led the research.

“Young birds will be exposed to fewer songs

from which they will build their own and this,

most likely, will lead to more simplified songs.”

Rise in asthma deaths

Deaths from asthma have risen by nearly a

third over the last decade, an analysis by the

charity Asthma UK has revealed. Last year,

1,422 fatalities were recorded in England and

Wales, compared with just over 1,000 in 2008.

The chief driver of the spike was an increase in

adult deaths; among under-14s, deaths have

remained broadly consistent, at between 12

and 27ayear. The charity attributed the rise

to acombination of increased air pollution, a

succession of hot summers (which drive up hay

fever,atrigger for asthma) andafailure by

sufferers and medical professionals to take the

disease seriously enough.

Honeycreepers:asad tune

Past research has often found that teenagers who spend

the most time on social media are also most prone to

anxiety and depression.Anew study suggests that while

there isacorrelation, social media is less to blame than

the negative factors–inparticular, lack of sleep and

cyberbullying–that it can result in. Researchers from the

UCL Great Ormond Street Institute of Child Health revisited

data on nearly 10,000 teenagers in England interviewed

three times between 2013 and 2015. As well as being

asked about social media use and overall well-being, they

were quizzed on aspects of their wider lifestyles.

Teenagerswho used social mediamostoften were most

likely to show signs of psychological distress–although

the correlation was more marked in girls than in boys. But

once the researchers factored in sleep and exposure to

cyberbullying, most of the association disappeared. Prof Russell Viner, who led the research, said

that frequent use of social media “may disrupt activities that haveapositive impact on mental

health such as sleeping and exercising”, while increasing the likelihood of being bullied online.

Technique for

separating

sperm by sex

Scientists in Japan have

developedatechnique for

separating sperm by sex,

using it to produce litters

of mice, pigs and cows in

which around 90% of

offspring conform to the

desired sex. And they

admit the technique,

outlined in PLOS Biology,

could potentially be

applied to humans, making

it possible for those under-

going IVF to select their

child’s sex prior to

fertilisation.

The team, from Hiroshima

University, chanced upon

the method while studying

the differences between X

(female) andY(male)

sperm cells in mice. Sperm

withXchromosomes, they

discovered, carry more

genes thanYones, and so

produceawider range of

protein receptors. When

they usedachemical to

bind to theXsperm’s

receptors, they found that

the sperm swam more

slowly–enabling them to

be separated fromYsperm.

The technique could be

used to make the dairy

industry more humane,

by reducing the number

of surplus males (many of

which are slaughtered at

birth). But if human sperm

are found to contain the

same receptors, it could

also make it possible for

IVF clinics to produce

embryos ofaselected sex.

Embryos produced by IVF

can already be screened for

sex –and in some countries,

including the US, growing

numbers of parents are

using this method to choose

achild’s sex. However, the

new technique could

hugely extend sex selection,

and raises ethical concerns.

“Sex skewing in humans

would be an ethical mine-

field with the potential for

unpredictable and disrup-

tive social consequences,”

said Dr Peter Ellis, a

molecular biologist at the

University of Kent.

Social media not directly to blame for teen mental health crisis

Is the stress linked to sleep deprivation?