Link between female birth weight and likelihood of breast cancer

dudara

From the BBC News website

Big babies 'risk breast cancer'

Baby girls who are of larger than average length and weight at birth grow up being at increased risk of breast cancer, analysis suggests.

The analysis of 32 studies involving more than 600,000 women provides the strongest evidence yet of such a link.

The London School of Hygiene and Tropical Medicine team says birth size might explain 5% of all breast cancers.

It could point to some link between cancer and the environment of the baby before birth, PLoS Medicine reports.

One theory is that a larger baby may be exposed to more oestrogen and other hormones in the womb.

The data analysed by Professor Isabel dos Santos Silva showed birth weight, length and head circumference were all linked with breast cancer risk.

A 0.5kg (1.1lb) increment in birth weight was associated with an estimated 7% increase in the risk of breast cancer.

But birth length appeared to be the strongest independent predictor of risk.

The risk of developing breast cancer by the age of 80 was 11.5 in 100 for the women who measured more than 51cm (20in) in length at birth, compared with 10 in 100 for those who had measured less than 49cm (19.3in).

This increase in risk, although modest, is of a similar magnitude to that of other more established risk factors for breast cancer, such as alcohol consumption, say the authors.

Professor dos Santos Silva said: "Little is known on how the pre-natal environment may affect breast cancer risk in later life. Further research is needed."

Dr Sarah Cant of Breakthrough Breast Cancer said: "Breast cancer is a complex disease that can be influenced by many factors throughout a woman's life.

"We don't yet know what all of these factors are, so it is very interesting that birth size may be one of them.

"This research could add to our increasing knowledge about the causes of breast cancer - possibly helping us to better predict breast cancer risk and potentially prevent the disease in the future."

She added that although there was nothing a woman could do about her size at birth, she could help reduce her risk of developing breast cancer with actions such as maintaining a healthy weight, eating a balanced diet and limiting her alcohol intake.

A spokeswoman for Breast Cancer Care said: "We would urge all women, particularly new mothers who may be worried by this study, to remember that gender and age are by far still the biggest known risk factors for developing breast cancer, with the majority of cases occurring in women aged over 50.

"Therefore, it is vital that all women remain breast aware throughout their lives and accept regular invitations to routine screening."

Around 46,000 cases of breast cancer are diagnosed every year in the UK. The disease kills an estimated 12,400 women annually.

I wonder if there is such a simple link between breast cancer and birth rate?

Dfens

Would this also hold true for big birth baby boys and male breast cancer?

tallaght01

Is it just because people in higher socio-economic groups have bigger babies, by and large? They also get more breast cancer, as they tend to have less kinds and get pregnant later.

dudara

It's an interesting observation, but is there any true link? I don't think so. Our western society is producing bigger babies and we also know that our western lifestyle can result in higher rates of cancer.

They don't say in the article what the structure of the sample set used was. Maybe the Journal article does. That might help illuminate the results.

G&T

I would worry if the risk of getting cancer was before the age of
65,My granny got cancer at 79,the doctors said it was
her body breaking down.She died in her sleep at 81,of old age.
I was 9lbs13oz at birth,
I had a lump in my breast and when I saw the doctor he asked for family history,told him about my grandmother and he said not to worry
I wasn't "at risk", only need worry if the cancer comes to the family before 65
What is the point of knowing this,
the only way to keep the birth weight down is to
smoke or diet during pregnancy!

What do they say one in 5 get cancer,
I think they should put the money into finding a cure for the disease,
we already know "everything"causes cancer.

tallaght01

dudara wrote: »

It's an interesting observation, but is there any true link? I don't think so. Our western society is producing bigger babies and we also know that our western lifestyle can result in higher rates of cancer.

They don't say in the article what the structure of the sample set used was. Maybe the Journal article does. That might help illuminate the results.

Well, people in higher socio-economic groups have bigger babies.

People in higher socio-econonomic groups get more breast cancer (probaby because they have less pregnancies, and they get pregnant later).

"Western society" factors play some role in the increased cancer levels I'm sure. But bear in mind that we're healthier now than people used to be. Also bear in mind that we now live longer than people used to. If we live longer, we're more likely to get cancer.

I'm just wondering if they factored this in. I'm sure they did. I don't have the journal reference, so I don't know.