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An hour a day keeps the doctor away
Children and adolescents who consistently watch television
for 2 hours or more a day are at an increased risk
of being overweight, to smoke, and to have high cholesterol
concentrations in early adulthood—substantial
risk factors for long-term health problems in later
life—conclude authors of a study from New Zealand
in last weeks issue of The Lancet.
Previous research has identified associations between
television viewing and poor health outcomes such as
high cholesterol and obesity; no longitudinal study
has assessed these effects into adulthood. Robert Hancox
(University of Otago, New Zealand) and colleagues studied
around 1000 children born in Dunedin, New Zealand,
in 1972–73 who were followed up at numerous intervals
to age 26 years. During this time parents (for children
aged 5–11 years) and adolescents (aged 13 years
and over) provided details of the duration of weekly
television viewing. Body-mass index (BMI), blood pressure,
cholesterol concentration, and cardiovascular fitness
was then assessed at 26 years of age.
A clear association was found between extensive television
viewing (more than 2 hours a day) among children and
adolescents and increased BMI, raised cholesterol,
greater proportion of smoking, and poor cardiovascular
fitness at age 26 years; no association was found between
television viewing and blood pressure. These associations
remained after adjustment for potential confounding
factors such as childhood socioeconomic status, BMI
at age 5 years, parental BMI, parental smoking, and
physical activity at age 15 years. The investigators
estimate that among all 26-year-olds, 17% of overweight,
15% of raised blood cholesterol, 17% of smoking, and
15% of poor fitness can be attributed to watching television
for more than 2 hours a day during childhood and adolescence.
“Although the adult health indicators that
we have found to be associated with child and adolescent
television viewing are unlikely to result in clinical
health problems by the age of 26 years, they are well
established risk factors for cardiovascular illness
and death later in life. Our results suggest that excessive
television viewing in young people is likely to have
far-reaching consequences for adult health. We concur
with the American Academy of Pediatrics that parents
should limit children’s viewing to 1–2
hours per day; in fact, data suggest that less than
1 hour a day would be even better.” States Dr.
Hancox.
AUSFTA sparks debate over bilateral vs. multilateral trade deals
The Senate debate over the Australian-United States
Free Trade Agreement is end next month. Regardless
of the verdict, the decision will mark a turning
point for Australian trade policy.
A vote in favour of the FTA would indicate that Australia
is now committed to preferential, bilateral trade agreements.
Although this would not be the first such agreement
to be signed by Australia the US agreement is much
more defining in terms of the surrounding policy discussion
than its two predecessors. A "yes" vote in
the Senate would in essence mark the end of the policy
debate over multilateral versus bilateral trade.
Following the preferential trade route raises a fundamental
concern over how the Government and its trade officials
can ensure that the negotiation of a series of agreements
remains in best interests of Australian exporters and
importers. Proponents of bilateral deals, however,
claim they are the cornerstones of developing a world
of freer multilateral trade. Yet, the risk that the
spread of a web of complex, and potentially inconsistent,
rules of origin could actually come to represent a
significant barrier to international trade flows.
In contrast, a “no” could signal the
end of bilateral trade agreements as a policy option
for Australia. If the preferential route gets blocked,
the multilateral option would be left to flourish.
Proponents of multilateral agreements argue that
future multilateral agreements under the auspices
of the WTO would be in Australia's national interest,
and that significant progress in the multilateral
arena would almost certainly bring much greater benefits
than any preferential agreement.
A wetter future for Australia?
Recent research published in the International Journal
of Climatology has shown that over the past 50 years
less water is evaporating from the land surface in
many regions of Australia. In addition, rainfall
has remained constant or even increased a little,
effectively making the land wetter. Much of the research
to date has been undertaken in the Northern Hemisphere,
but a new report details the changes specific to
Australia between 1970 and 2002.
In the time period studied, rainfall in the various
regions of Australia did not show a significant trend.
However, the average amount of evaporation showed a
significant decrease. Thus, despite unvarying rainfall,
the land surface of Australia has become less arid
over the past three decades. One of the appreciable
impacts of decreased evaporation in water-limited areas
is less moisture deficit that could possibly result
in increased biological productivity and an increase
in carbon uptake.
The apparent change is in direct contradiction to
predictions made by the Intergovernmental Panel on
Climate Change (IPCC). This group, as well as others,
expected that as the average air temperature near the
land surface increased so would the potential for evaporation.
The authors of the research findings, Michael Roderick
and Graham Farquhar, do not yet know the cause of the
change in evaporation rate. One possibility, not ruled
out by this study, is the enhanced greenhouse effect.
The authors use the analogy of a gardener’s ‘greenhouse’ to
describe the warmer and effectively wetter terrestrial
surface observed.
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