Several studies have shown a positive correlation between parity and reduced hip fracture rate later in menopause while others have shown no correlation or a negative one. Thus, it is possible that some of the conflicting results reported in literature may be attributable to differences in the ages of the populations studied or of the concomitant presence or not of osteoporosis.
In order to elucidate these conflicting results, a population based observational retrospective study has been performed at 160 centers all over Greece. The fracture rate of 4616 postmenopausal osteoporotic women (PMOW) (mean age=64.1±9.3 years) has been compared with the number of their children. Patients have been divided into two main groups. Group A consisted of women with two or less children and Group B of women with 3 and more children. Descriptive statistics like the mean±S.D. and frequencies were used to present the data. In order to assess for relationships between categorical variables the χ2 test was performed. Statistical analysis was conducted using the software SAS, version 9.1 and statistical significance was established as 5%. The results are as follow:
1. 16.2% of these PMOW had a history of fracture and for 80.3% of them was a hip fracture.
2. There was no correlation of the parity in general and the rate of fracture (P=0.6887).
3. Group B women had higher fracture rate than Group A women which was a statistically significant result (P<0.05).
It can be concluded that more fracture-susceptible PMOW are those having three children or more. It seems that the beneficial effect of multiparity on BMD, as it has been described by others, may be lost after menopause especially in an osteoporotic population.