(Press-News.org) Women who experience significant weight gain after the age of 20 and either have their first child after the age of 30 or don’t have children are almost three times more likely to develop breast cancer than those who give birth earlier and whose weight remains relatively stable, new research from the UK being presented at this year’s European Congress on Obesity (ECO 2025) has found.
Previous research has shown that weight gain in adulthood increases the risk of developing breast cancer after the menopause.
Other research has found that an early first pregnancy may cut the risk of breast cancer. For example, a review of 21 studies on reproductive risk factors for breast cancer reported that each additional year of age of first full-term pregnancy adds 5% to the risk of premenopausal breast cancer and 3% to the risk of postmenopausal breast cancer.1
However, the combined effect of these two factors and whether weight gain has less effect on breast cancer risk if a woman has an early first pregnancy, has yet to be established.
Breast cancer is one of the most common cancers worldwide, with 2.3 million diagnoses in women in 2022 and 670,000 deaths.2 In the UK, where it is the most common cancer, there are almost 57,000 cases and 11,500 deaths a year.3
“In England, the proportion of the women with obesity or overweight has increased from 49% in 1993 to 59% in 20214, and the proportion of women giving birth later in life has been steadily increasing over the past 50 years5”, says lead researcher Lee Malcomson, of the University of Manchester, Manchester, UK.
“Meanwhile, diagnoses of breast cancer in women are at their highest ever rate.6 More information about how age of motherhood and weight gain affect the risk of breast cancer, would allow us to better work out who is most at risk of the disease and target lifestyle advice accordingly.”
For the study, Mr Malcomson and colleagues analysed data on 48,417 women (median age 57 years, median BMI 26.3 kg/m²) who took part in PROCAS7, a large UK study of women attending breast screening.
The women were categorised based on whether they had their first pregnancy early (before the age of 30 years), late (aged 30 years or older) or were nulliparous (had not given birth) and weight gain in adulthood. Weight gain was calculated by asking participants to recall their weight at the age of 20 and subtracting it from their current weight. The women were followed up for a median of 6.4 years, during which 1,702 were diagnosed with breast cancer.
Analysis of the results found that women with an early first pregnancy had greater weight gain during adulthood than those with a late first pregnancy, with 0.21kg of additional weight gain for each year earlier the pregnancy occurred.
It also confirmed the literature that an early first pregnancy protects against post-menopausal breast cancer and that adult weight gain is associated with an increased risk of the disease.
However, the study found no evidence that having a first pregnancy at an early age reduces the increased breast cancer risk caused by weight gain.
It did show that women who had a greater than 30% increase in weight during adulthood and either had their first child after age 30, or did not have children, were nearly three times more likely (2.73 times) to develop breast cancer compared with women who had an early first pregnancy and less than a 5% increase in adult weight.
Mr Malcomson concludes: “Our study is the first to establish how weight gain and age of first birth interact to affect a woman’s risk of breast cancer.
“It is vital that GPs are aware that the combination of gaining a significant amount of weight and having late first birth - or, indeed, not having children - greatly increases a woman’s risk of the disease.”
He added that the results also align with advice to keep a healthy weight and exercise to cut the risk of breast cancer.
Sub-analyses of data on women with ER positive breast cancer (the most common form of breast cancer), ductal carcinoma in situ (DCIS – a very early form of breast cancer), breast cancer detected during screening and post-menopausal participants had similar results.
END
The combination of significant weight gain and late motherhood greatly increases a woman’s risk of breast cancer, UK study finds
2025-05-09
ELSE PRESS RELEASES FROM THIS DATE:
Weight-loss drugs cut alcohol intake by almost two-thirds, research in Ireland suggests
2025-05-09
Individuals who take liraglutide or semaglutide for weight loss reduce their alcohol consumption by almost two-thirds in four months, new research being presented at this year’s European Congress on Obesity (ECO 2025) has found.
Alcohol use disorder is a relapsing condition that accounts for 2.6 million deaths a year – 4.7% of all deaths globally.
Treatments such as cognitive behavioural therapy (CBT), therapies that aim to strengthen motivation to stop or reduce drinking and medication can be very successful in the short-term, however, 70% of patients relapse ...
Swedish study explores differences in how the sexes break down fat
2025-05-09
The research focused on lipolysis, the process through which triglycerides – lipids stored in fat cells – are broken down to produce free fatty acids and glycerol, which can be used as energy, during exercise or between meals.
“The breakdown of lipids through lipolysis is essential for energy balance and it is believed that doing it effectively may prevent type 2 diabetes and other metabolic complications of overweight and obesity,” says Professor Peter Arner, of the Karolinska Institutet, Stockholm, ...
Antibiotics taken during infancy linked to early puberty in girls
2025-05-09
Girls given antibiotics during their first year of life, especially in the first three months, are more likely to enter puberty at an earlier age, according to research presented at the first Joint Congress between the European Society of Paediatric Endocrinology (ESPE) and the European Society of Endocrinology (ESE). The likelihood of early puberty was also higher among those exposed to a greater variety of antibiotic classes. The findings highlight the importance of using these medicines in infants appropriately ...
Real-world evidence links long-term use of oral and inhaled steroids to adrenal insufficiency
2025-05-09
Individuals taking steroid tablets for more than 3 months are over 6 times more likely to be diagnosed with adrenal insufficiency than those treated with non-steroidal anti-inflammatory drugs, according to research presented at the first Joint Congress between the European Society of Paediatric Endocrinology (ESPE) and the European Society of Endocrinology (ESE). In addition, they have a greater risk of being hospitalised for adrenal insufficiency, while long-term users of inhaled steroids have an increased risk of developing adrenal insufficiency but without any increase in the number of hospitalisations. The findings ...
Phthalates may impact key genital measurement in 3-year-olds
2025-05-09
Three-year-old boys are more likely to have a shorter anogenital distance when their mothers have high levels of phthalates in their urine, according to research presented at the first Joint Congress between the European Society of Paediatric Endocrinology (ESPE) and the European Society of Endocrinology (ESE). In girls, the direct exposure to phthalates was associated with a shorter anogenital distance. The findings highlight how exposure to environmental pollutants can cause alterations in genital measurements during the first three years of life, which may affect sexual development and fertility later in life.
Phthalates ...
Phosphate levels in blood strongly affect sperm quality in men
2025-05-09
Men with fertility issues have lower levels of phosphate in the blood than average, according to research presented at the first Joint Congress between the European Society of Paediatric Endocrinology (ESPE) and the European Society of Endocrinology (ESE). In addition, low phosphate concentrations in the blood were associated with reduced sperm motility in infertile men. The findings can help researchers improve the understanding of the biological factors involved in male reproductive health, which could lead to new fertility treatments.
Over the past 50 years, sperm counts worldwide have halved, sperm quality has declined alarmingly and 15% of all heterosexual couples are ...
Testosterone during pregnancy linked to physical activity and muscle strength in children
2025-05-09
Boys born to mothers who have polycystic ovary syndrome (PCOS) or who have higher levels of testosterone during the third trimester are more likely to be less physically active at age 7, according to research presented at the first Joint Congress between the European Society of Paediatric Endocrinology (ESPE) and the European Society of Endocrinology (ESE). Testosterone levels or PCOS in the mothers were not associated with physical activity in girls, but 7-year-old girls whose mothers had higher testosterone levels during pregnancy had lower muscle strength. The findings highlight the important role that maternal testosterone and PCOS may play in future development in boys and girls ...
Menopause at an earlier age increases risk of fatty liver disease and metabolic disorders
2025-05-09
Women who experience menopause before the age of 50 — and especially before the age of 45 — are more likely to develop fatty liver disease and its related metabolic risk factors within one year after menopause, according to research presented at the first Joint Congress between the European Society of Paediatric Endocrinology (ESPE) and the European Society of Endocrinology (ESE). This study is the largest to assess this association over five years and suggests that the age of natural menopause should be considered part of the cardio-metabolic risk assessment ...
Early-life growth proved important for height in puberty and adulthood
2025-05-09
Growth patterns during the first two years of a child’s life may shape pubertal growth and adult height, but have little effect on pubertal timing, according to research presented at the first Joint Congress between the European Society of Paediatric Endocrinology (ESPE) and the European Society of Endocrinology (ESE). The findings highlight the importance of early-life growth, which could be used as a marker to predict future growth, development and health.
It is well established that the early-life growth period — from conception to approximately two years of age — is crucial ...
Women with infertility history at greater risk of cardiovascular disease after assisted conception
2025-05-09
Women who experience infertility are more likely to develop heart and blood vessel conditions later in life, with younger women and those who undergo fertility treatments at a greater risk. The findings, presented at the first Joint Congress between the European Society of Paediatric Endocrinology (ESPE) and the European Society of Endocrinology (ESE), highlight the importance of considering a woman’s reproductive history when assessing her long-term heart health.
Approximately one in every six people of reproductive age worldwide is estimated to experience infertility in their lifetime. Treatment of infertility ...