likely to develop dementia, new research
has found. For the cohort study, scientists
in Canada examined health data on some
6.6 million adults in the province of
Ontario over 12 years, and, by looking at
their postcodes, divided them into groups
according to how far they lived from “a
major thoroughfare with medium to large
traffic capacity”. Once they had adjusted
the figures for various factors, including
preexisting illnesses, and whether the
subjects lived in urban or rural areas, they
found those whose homes were within
50 metres of a busy road were 7% more
likely to be diagnosed with dementia than
those who lived at least 300 metres away.
Traffic pollution contains a number of
damaging toxins, including nitrogen oxide.
However, the study has proved no
causative link and has clear limitations: for
instance, it was based on where people
lived at a point in time before the study
began; we know nothing about their
subsequent exposure to pollution.
