Premature gonadal insufficiency: etiology and long term reproductive and health outcomes

Research group information

Contact information

Research group leader

  • Docent, Specialist in obstetric and gynecology and reproductive medicine
    Maarit Niinimäki

Research group description

The average age of menopause in Western countries is 51 years. However, the decline in ovarian function begins about 10 years earlier, eventually leading to the cessation of oestrogen secretion and menstruation. The age of menopause significantly increases a woman's risk of cardiovascular disease and impairs glucose metabolism. In addition to oestrogen, vitamin D, a hormone that regulates bone metabolism, has also been linked to cardiovascular risk. In men, testosterone secretion gradually declines with age. Testosterone deficiency, hypogonadism, occurs when testosterone levels fall below 12 nmol/l. It may be caused by testicular insufficiency or by disturbed hypothalamic-pituitary axis. In men, low testosterone levels have been found to be associated with an increased risk of cardiovascular disease and diabetes. There may also be an increased risk of osteoporosis.

Premature ovarian insufficiency (POI) refers to the cessation of menstruation before the age of 40 and early menopause (EM) refers to the cessation of menstruation before the age of 45. Diagnosis is based on the absence of menstruation, low oestrogen levels and high FSH hormone levels. Symptoms may include menopausal symptoms such as hot flashes, sweating, vaginal dryness and sleep disturbances. The incidence of POI is estimated to be around 1% and that of EM around 10%. The aetiology of POI and EM are complex; for example, the cause may be genetic, autoimmune or iatrogenic (e.g. radiotherapy, chemotherapy or oophorectomy). The effects of environmental factors are not well understood, but at least smoking is known to precipitate menopause. Often the aetiology remains unclear. Studies suggest that menopausal side effects occur earlier in POI women. Currently, there are no studies on the effects of hormone replacement therapy on long-term morbidity. POI also affects fertility and the number of children.

Vitamin D is formed in the skin by ultraviolet radiation from the sun. In northern latitudes, the amount of sunlight is low, so without vitamin D supplementation the population is at increased risk of vitamin D deficiency. Vitamin D receptors have been found in the uterus and ovaries. It is a steroid hormone with a controversial role in the regulation of reproduction. In some small studies, vitamin D deficiency has been found to increase the risk of miscarriage. These studies have been conducted mainly in small and selected samples.

Our Team

Where are we headed

The studies aim to provide new information on I ) etiology and consequences of POI and EM II ) Genetic background of POI (FinnGEN collaboration) III the effect of vitamin D on reproductive health and IV ) the association between low testosterone levels in men and long-term morbidity

Our main collaborators

  • Kristiina Aittomäki, prof Helsinki University, genetics
  • Leena Ala-mursula, prof Oulu University, Occupational Health
  • Juha Auvinen, prof Oulu University, Public Health
  • Mika Gissler, prof Department of Health&Welfare, Karolinska Institutet Sweden
  • Karl-Heinz Herzig, prof Oulu University, Physiology
  • Marjo-Riitta Järvelin, prof Oulu University, Imperial College UK
  • Johannes Kettunen, prof Oulu University, Biocenter Oulu
  • Erika Jääskeläinen, prof Oulu University, psychiatry
  • Triin Laisk, dos Tartu University, Estonia
  • Hannele Laivuori, prof Tampere University, ob&gyn
  • Hannu Martikainen, prof Oulu University, ob&gyn
  • Jouko Miettunen, prof Oulu University, psychiatry
  • Outi Uimari, MD PhD Oulu University, ob&gyn
  • Terhi Piltonen, prof Oulu University, ob&gyn
  • Eero Pukkala, prof Cancer Register, Tampere University
  • Sylvain Sebert, prof Oulu University, ELITE
  • Juha Tapanainen, prof Helsinki University, ob&gyn    

How to find us