Kevan Christie: Scientific research is rarely the final word, as knowledge grows

There has been contradictory advice over hormone replacement therapy for the menopause
There has been contradictory advice over hormone replacement therapy for the menopause
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The U-turn over hormone replacement therapy for the menopause raises a number of questions around the potential benefit of revisiting previous medical research that may have been incorrect.

Women are being told they can take HRT without fear of it killing them a long-term study has concluded.

However, the same study originally raised fears that cases of breast cancer, heart attack and stroke were more prevalent among women who took HRT – oestrogen alone or in combination with progestin, a synthetic hormone.

In this instance scientists returned to the data on 27,000 women aged 50-79 who took HRT for five to seven years used in the 2002 study from the US Women’s Health Initiative.

Crucially, researchers followed them for a longer period – an average of 18 years – and found that death rates were unaffected by the treatment, with 27.1 per cent dying during this period among those who took hormones against 27.6 per cent who took a placebo.

Heart disease deaths were also identical and there was no significant difference in the risk of dying from cancer – 8.2 per cent for those on HRT against 8 per cent in the control group.

So, a generation of women who may have benefited from hormone therapy to manage symptoms such as hot flushes and night sweats were put off taking it based on flawed research that appears to have been conducted over the wrong timeframe.

This leads me to question what else is out there, that has been accepted as gospel and embellished by a media quick to grab headlines.

One example that springs to mind but is in no way a direct comparison is the MMR vaccine controversy which started with the 1998 publication of a fraudulent research paper in the Lancet and ended in tears when the claim was made that colitis and autism spectrum disorders were linked to the combined measles, mumps and rubella (MMR) vaccine.

Again, the media were quick to jump on the bandwagon with scaremongering coverage, described in 2011 as “perhaps the most damaging medical hoax of the last 100 years”.

Investigations uncovered that Andrew Wakefield, the author of the original research paper, had multiple undeclared conflicts of interest, had manipulated evidence and had broken other ethical codes. The Lancet paper was partially retracted in 2004, and fully retracted in 2010, when editor-in-chief Richard Horton described it as “utterly false” and said that the journal had been “deceived”.

So, my point is the research that appears in medical journals can never be taken at face value and a wide range of opinion should always be sought.

Other examples of research chopping and changing can be found in the never-ending stream of conflicting information around things like alcohol, obesity and cholesterol. Sugar is another research minefield.

For years we were told to limit the number of eggs that we ate as they contain dietary cholesterol: turns out eggs were not the problem but too much saturated fat found in butter and meat products (pies).

Thankfully, most expert opinion these days carries the caveat that more research is required and a declaration of interest is a standard requirement. It’s also worth noting that often there is no black and white answer to health matters and we may have to learn to live with the grey areas.