BMJ No 7015 Volume 311. This Week in BMJ
It has recently been hypothesised that an increased intake of polyunsaturated
fats or decreased intake of cholesterol and saturated fat might explain the
inverse association between low concentrations of serum cholesterol and an
increased risk of cancer. Zureik et al (p 1251) prospectively assessed the
association of fatty acid proportions in cholesterol esters, used as biological
markers of dietary fat intake, with the risk of premature death from cancer in
3277 middle aged French men during an average of 9-3 years of follow up.
Increased proportion of linoleic acid and decreased proportions of oleic and
palmitoleic acids in cholesterol esters were strongly associated with a reduced
risk of death from cancer. Consistently, increased intake of polyunsaturated
fat was associated with a reduced risk of such death. The findings suggest that
intake of polyunsaturated fat does not increase the risk of death from cancer
and cannot explain the association between low cholesterol and cancer.
Modernisation of lifestyle in developing countries is associated with the
seemingly inevitable emergence of non-communicable diseases such as non-insulin
dependent diabetes mellitus, coronary heart disease, and stroke. On p 1255
Dowse et al report the results of a national, non-communicable disease primary
prevention programme in Mauritius, which has rates of diabetes and coronary
heart disease among the highest in the world. Between 1987 and 1992 the
prevalence of hypertension, smoking, and excessive alcohol consumption
decreased. The prevalence of obesity, however, increased. A pronounced fall in
population serum cholesterol concentrations was probably related to a reduction
in the saturated fat content of a common cooking oil. Lifestyle intervention
programmes for non-communicable diseases can be implemented in developing
countries.
Studies of the outcome of depression in general practice have yielded
conflicting results. The effect of diagnosis by, or disclosure of depression
to, general practitioners is also unclear. Dowrick and Buchan (p 1274)
prospectively studied the 12 month outcome of episodes of depressive illness in
179 attenders at two general practices, including the effects of disclosure of
undetected depression. They found that no difference in outcome was seen
between subjects whose depression was detected by their general practitioner
and those whose depression was disclosed to their general practitioner.
Moreover, the subjects whose depression was diagnosed and for whom there was an
identifiable intention to treat tended to have a worse result than those whose
condition remained undetected. The authors conclude that a diagnosis of
depression should be regarded simply as a marker of the severity of the
depression.
To reduce the risk of coronary heart disease, populations have been advised to
reduce intake of saturated fat, but an individual approach may be warranted in
the light of a study from New Zealand. Cox et al (p 1260) challenged 67
volunteers with a change in the nature of dietary fat on two occasions to
determine whether plasma lipid concentrations are consistently sensitive to
changes in saturated fats and to examine whether it is possible to identify a
group of people who consistently have a large or small response. They found a
consistency in cholesterol response that was not explained by dietary
compliance, and within their hypercholesterolaemic subjects there were groups
of consistent hyperresponders and minimal responders. Response to dietary fat
was predicted by initial cholesterol concentration and concentrations of
apolipoprotein B and triglycerides. Such data may help to identify individuals
likely to benefit from targeted dietary advice.
Several studies have shown that anticipation of job change or loss has an
adverse effect on morbidity. On p 1264 Ferrie et al show that among white
collar civil servants the anticipation of job change or loss was associated
with a relative decline in self reported health status that was not accompanied
by a relative worsening in the profile of health related behaviours. The
application of a longitudinal design, allowing the same individuals to be
followed from job security into anticipation of job loss, enables these results
to extend existing knowledge as health status before the anticipation phase was
controlled for.
Bed sharing has been linked to an increased risk of the sudden infant death
syndrome. Possible reasons include overheating, an interaction between bed
sharing and maternal smoking, consumption of alcohol the night before the
death, and asphyxia from overlaying combined with parental consumption of
alcohol or drugs. Klonoff-Cohen and Edelstein (p 1269) describe a case-control
study of 200 white, African-American, Latin American, and Asian infants who
died of the sudden infant death syndrome and 200 comparison infants matched for
birth hospital, date of birth, age, and sex. The results indicate that bed
sharing during the day was more common in African-American and Latin American
families than white families. A total of 22% (45) of deaths occurred while
sharing a bed. The overall adjusted odds ratios for routine bed sharing in the
daytime and at night, however, were not significant when routine sleep
position, passive smoking, breast feeding, infant birth weight, use of an
intercom, medical conditions at birth, and maternal age and education were
considered.