Cleverness `delays the menopause'

CLEVER WOMEN are more likely to have a delayed menopause because a key female hormone determining the length of female reproductive life may also influence the development of mental ability.

This is the main finding of a national survey of more than 1,500 women by the Medical Research Council, which tried to see if there was a link between early mental prowess and the onset of menopause. The study is part of the National Survey of Health and Development, which has followed the lives of thousands of people born in March 1946. Researchers focused on 1,572 women who had taken part in intelligence tests throughout their lives.

The research team, led by Dr Marcus Richards of University College London, tried to eliminate other factors that could have influenced the onset of menopause, such as smoking, drinking and social deprivation, which are known to bring it on earlier.

Each woman had at the age of eight taken part in standard intelligence tests, including the ability to pronounce words correctly and to finish sentences. They took further tests at 11, 15 and 26. At 43 they were tested for memory and concentration.

"Those women with lower scores in mental ability, especially at a young age, are more likely to have an earlier menopause than those who had higher scores," Dr Richards said.

However, he added that it is not possible to predict what a woman's delayed onset may by if she has a higher-than-average intelligence. "These are general trends in the population and there will always be exceptions to the rule," he said.

Because the researchers eliminated obvious explanations for the trend they observed, such as a girl's social background or physical development, they said it is most likely explained by the influence of oestrogen, the female hormone. Oestrogen levels fall as middle-aged women enter menopause and the hormone is a key determinant of reproductive lifespan. It is also known to target areas of the brain involved in developing mental ability, Dr Richards said. "The exact nature of the relationship is bound to be complicated and we are not suggesting there is a simple causal effect," he added.

Dr Richards said the link between the onset of menopause and mental ability was found to be independent of a woman's occupation. The findings do not automatically mean that professional women were more likely to have a later menopause than manual workers. "Obviously mental ability and occupation are related, but not precisely. There are people of high ability in low- paid jobs," Dr Richards said.

The researchers also found little comfort for men. Women tested at 43 who went on to start their menopause early still had, on average, higher IQ scores than men.