Oak pollen causes early hay fever symptoms, not birch or grass as previously believed, according to a seven-year study published in the British Journal of General Practice. It found the initial peak for patients reporting hay fever symptoms came after the birch pollen season but before the start of the grass pollen periods.

Using spermicides with a contraceptive diaphragm three times a week almost triples the risk of women developing cystitis and other urinary tract infections, a study published in the New England Journal of Medicine, has found. The researchers, from the University of Washington, think that spermicides might trigger changes in the vaginal flora which in turn promote the growth of certain pathogens.

One quarter of a million people are on steroid drugs for conditions such as rheumatoid arthritis and asthma - but few are receiving treatment to prevent steroid-induced brittle bone disease, according to a study from Nottingham University, published in the British Medical Journal. It found that only 14 per cent of patients on oral steroids received drugs to increase bone density and prevent osteoporosis, although they run twice the risk of suffering hip and other fractures.