eMJA: In Other Journals, 5 November 2007

Hypothalamopituitary dysfunction following traumatic brain injury (TBI) or aneurysmal subarachnoid haemorrhage (SAH) may be more common than previously thought, according to the authors of a recent systematic review. Researchers collected data from 19 studies including over 1000 patients and found the prevalence of hypopituitarism in TBI patients to be 27.5% in the chronic phase. Patients who suffered an aneurysmal SAH showed a prevalence of pituitary dysfunction of 47%. The authors comment that deficiencies of pituitary hormones such as growth hormone, the sex steroids, corticosteroids and thyroid hormone result in clinical consequences that may be difficult to diagnose and significantly contribute to morbidity in these patients.

Broken-hearted

The link between stress and cardiovascular disease has been further elucidated by a review of epidemiological studies on the subject. In an attempt to gather evidence for the association between stress and acute and chronic cardiovascular disease, researchers reviewed the literature and possible mechanisms mediating the response to psychological and physical stress. It appears that psychological stress elicits changes in the sympathetic-parasympathetic balance and the tone of the hypothalamic-pituitary-adrenal axis. The cardiovascular system may be acutely affected by triggering of arrhythmia, or the precipitation of myocardial ischaemia via impaired endothelium-mediated vasodilation at the microvascular level. Chronic stressors appear to be associated with cardiovascular disease through acceleration of atherosclerosis. The authors comment that there is clear evidence of genetic variation between individuals of this effect, and that there is great potential for therapeutic intervention.

Lancet 2007; 370: 1089-1100

Xeno-oestrogens

Serum xeno-oestrogenic activity may be measured and potentially used as a biomarker of occupational exposure to pesticides, according to Danish researchers. Using current reports of pesticides with oestrogen-like properties as a basis for their investigations, the authors analysed serum samples from pregnant and non-pregnant female greenhouse workers for xeno-oestrogenic activity. Workers were categorised as having low, medium or high exposure, depending on working conditions and level of contact with the relevant pesticides. After adjustment for confounders, xeno-oestrogenic activity appeared to be positively associated with the level of pesticide exposure in both groups of women. The response in serum of pregnant women was higher than in non-pregnant women, irrespective of the level of pesticide exposure. The researchers comment that the variability in activity of the biomarker within the groups made it less useful as a measure of exposure on an individual level.

Occup Environ Med 2007; 64: 708-714

Cholesterol all in the family

Screening children and their parents for familial hypercholesterolaemia simultaneously could be very useful in preventing the serious consequences of this disorder, British researchers have found. A meta-analysis was performed of available data on total and low-density lipoprotein cholesterol levels in people with and without familial hypercholesterolaemia. Data were analysed for detection rates according to age groups ranging between birth and over 60 years. Detection rates were best between the ages of 1 and 9 years, when serum cholesterol concentrations discriminated best between those with and without hypercholesterolaemia. Subsequent serum cholesterol measurement in the affected child’s parents is estimated to detect about 96% of parents with the condition.

BMJ 2007; 335: 599

The Pill and cancer — the facts?

Use of the oral contraceptive pill does not appear to be associated with an overall increased risk of cancer, and may have a net positive population effect, according to a large UK cohort study. Using data from the Royal College of General Practitioners’ oral contraception study, researchers analysed almost 340 000 woman-years of observation for never-users of oral contraceptives and 744 000 woman-years for ever-users. Women who had used oral contraceptives had statistically lower rates of cancers of the bowel, uterine body, ovaries, and main gynaecological malignancies combined. Small, statistically non-significant increases were found in the risk of lung, cervix and central nervous system cancers. No difference was found between the groups for breast cancer. In both groups, rates of any cancer increased with smoking and age. There was no evidence of an increased risk of cancer overall in users of oral contraceptives in this British cohort. Potential confounders were adjusted for in the analysis, and made little difference to the observed rates of cancer. The researchers point out that the strengths of the study include the very large number of woman-years of observation (over one million) and the length of the study, allowing most cancers to be “caught” as the subjects became postmenopausal. They comment, however, that the results may not be applicable to oral contraceptive users today, as currently available preparations may have different associated risks.

BMJ 2007; 335: 651

Dr Tanya Grassi, MJA

The Medical Journal of Australia eMJA