Association of growth from birth until middle age with sex hormone parameters and reproductive function in the Northern Finland Birth cohort 1966
Thesis event information
Date and time of the thesis defence
Place of the thesis defence
Auditorium 4, Oulu University Hospital
Topic of the dissertation
Association of growth from birth until middle age with sex hormone parameters and reproductive function in the Northern Finland Birth cohort 1966
Doctoral candidate
Licentiate of Medicine Johanna Laru
Faculty and unit
University of Oulu Graduate School, Faculty of Medicine, Clinical Research Unit, Medical Research Center (MRC)
Subject of study
Obstetrics and gynaecology
Opponent
Docent Tiina Laine, University of Helsinki
Custos
Docent Laure Morin-Papunen, University of Oulu
Childhood growth and maternal obesity are associated with later reproductive health
Obesity predisposes people to numerous morbidities and less well-known reproductive problems. In women, obesity increases the risk of infertility and polycystic ovary syndrome (PCOS). In men, obesity impairs reproductive health and is associated with testosterone (T) deficiency. Since the above-mentioned problems affect a significant proportion of the population, this study focuses on the association between early risk factors and reproductive problems, providing a great opportunity to identify the sensitive time periods for preventive actions.
The aim of this study was to assess the impact of prenatal factors, birth weight (BW), and BMI, from birth until middle age, on sex hormone levels and reproductive function in both women and men. The study populations (women and men with impaired reproductive function, women with PCOS and men with low T at age 31) were derived from the Northern Finland Birth Cohort 1966 with additional data from the Finnish Medical Birth Register. Multiple confounding factors, such as socioeconomic and lifestyle factors, marital status, attempts to have children, and adult obesity, could be considered.
The results revealed that in girls, obesity in mid-childhood and especially in puberty - and in boys, low BMI in early childhood - predicted impaired reproductive function, as well as an increased risk of childlessness regardless of confounding factors. In boys, overweight and obesity in early childhood was associated with a decreased risk of infertility, but BMI from mid-childhood onwards did not affect their subsequent reproductive function. Both women with PCOS and men with low T at age 31 already had higher weight gain from childhood onwards; their weight gain began earlier, and their BMIs remained higher until age 46. In boys, maternal obesity was associated significantly with later T deficiency, suggesting that metabolic factors during pregnancy affect boys’ endocrine function later in life. Lower BW and prematurity in girls were associated with PCOS later in life.
Given the well-known health risks related to obesity and the steadily rising prevalence of maternal obesity, the study results emphasize the importance of preventing obesity, maintaining an optimal growth during childhood, and preventing maternal obesity, as all these factors affect reproductive health later in life.
The aim of this study was to assess the impact of prenatal factors, birth weight (BW), and BMI, from birth until middle age, on sex hormone levels and reproductive function in both women and men. The study populations (women and men with impaired reproductive function, women with PCOS and men with low T at age 31) were derived from the Northern Finland Birth Cohort 1966 with additional data from the Finnish Medical Birth Register. Multiple confounding factors, such as socioeconomic and lifestyle factors, marital status, attempts to have children, and adult obesity, could be considered.
The results revealed that in girls, obesity in mid-childhood and especially in puberty - and in boys, low BMI in early childhood - predicted impaired reproductive function, as well as an increased risk of childlessness regardless of confounding factors. In boys, overweight and obesity in early childhood was associated with a decreased risk of infertility, but BMI from mid-childhood onwards did not affect their subsequent reproductive function. Both women with PCOS and men with low T at age 31 already had higher weight gain from childhood onwards; their weight gain began earlier, and their BMIs remained higher until age 46. In boys, maternal obesity was associated significantly with later T deficiency, suggesting that metabolic factors during pregnancy affect boys’ endocrine function later in life. Lower BW and prematurity in girls were associated with PCOS later in life.
Given the well-known health risks related to obesity and the steadily rising prevalence of maternal obesity, the study results emphasize the importance of preventing obesity, maintaining an optimal growth during childhood, and preventing maternal obesity, as all these factors affect reproductive health later in life.
Last updated: 23.1.2024