ABSTRACT. All women (n = 11809) aged 44–53 years from a representative district of Denmark were asked by questionnaire about their date of birth, date of latest menstrual bleeding, possible gynaecological operations, smoking habits, and use of medications. A total of 9411 (80%) questionnaires were returned. After exclusions because of incomplete information (n = 275), possible surgical menopause (n = 1270), and treatment with gonadal hormones (n = 2 221), 5 645 women remained suitable for the study. The reproducibility of the information given by these women was excellent as judged by personal interviews of 315 participants. The study population was divided into five 2‐year age groups, and the proportion of postmenopausal women among non‐smokers and heavy smokers was calculated. Differences in respect to the menopausal status were not observable in the oldest and the youngest two age groups comprising just a few per cent of postmenopausal women. However, heavy smokers in the other two age groups had passed the menopause earlier than the non‐smokers (p<0.001). This finding suggests cigarette smoking as a promotor of the menopause.

In conclusion, adenoma cells seem to react in almost the same way as normal parathyroid cells. They respond to initiation of hypocalcaemia by the release of preformed PTH(1-84), and continue to secrete increased amounts of PTH(1-84) during the maintenance of relative hypocalcaemia. The increased baseline concentrations of blood ionized calcium and serum PTH(1-84) and the serum PTH(1-84) response during blood ionized calcium lowering all suggest a shift upwards in the calcium set point.