Long-term restoration of deficits in bone mineral density is inadequate in premenopausal women with prior menstrual irregularity.
OBJECTIVE
To investigate change in bone mineral density (BMD) in premenopausal women (age, 29-46 years), some of whom were marathon runners with a history of menstrual irregularity.


METHODS
Longitudinal follow-up.


METHODS
University medical school.


METHODS
We investigated 8 sedentary controls (SC) and 19 marathon runners (12 with regular menses (R) and 7 with a history of irregularity (OA) 11.7 +/- 7.9 years before follow-up).


METHODS
BMD (g/cm2) of lumbar spine (LS) and proximal femur were determined at baseline and follow-up (3-5 years later). We calculated a menstrual history index (MHI) (estimated periods/year since age 13).


RESULTS
Body mass, age at menarche, and femoral BMD were not statistically different. Follow-up LS BMD (g/cm2) was lower (p < 0.01) in OA (0.936 +/- 0.060) than in R (1.043 +/- 0.103) and SC (1.094 +/- 0.077), even when covarying for age or both age and mass. No group changed BMD significantly with time. Current MHI was lower (p < 0.001) in OA (9.7 +/- 1.4) than in R (11.3 +/- 0.5) and SC (11.8 +/- 0.4). MHI for the teenage years was lower in OA than in SC but not in R. OA had significantly lower MHI than did R and SC for the third and fourth decades. Only MHI during the third decade correlated significantly with LS BMD for all subjects.


CONCLUSIONS
Restoration of LS BMD deficit in women with prior menstrual irregularity aged over 30 is slow and may never reach the same level as age-related controls; secondly, this may be the result of both bone loss in the third decade of life and reduced acquisition during adolescence.
Department of Physiology, University of Cape Town Medical School, South Africa.
L K
LK
Micklesfield
L
L
Reyneke
A
A
Fataar
K H
KH
Myburgh
D000328:Adult; D000568:Amenorrhea / Q000503:physiopathology; D015519:Bone Density; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008599:Menstruation Disturbances / Q000503:physiopathology*; D008875:Middle Aged; D009839:Oligomenorrhea / Q000503:physiopathology; D017697:Premenopause; D012420:Running / Q000502:physiology