The frequency distribution of age at natural menopause among Saudi Arabian women

Objective: Hormonal changes at the menopause are associated with the onset of a number of medical conditions. The distribution of age-at-menopause (AAM) within a given population can, therefore, indicate how the disease prevalence changes with age. The objective of this study was to estimate the distribution of AAM among Saudi Arabian women, in order to predict local trends in the prevalence of osteoporosis. Methods: Patient age, AAM, medical history and associated information for 858 Saudi Arabian women were extracted from a Dual Energy Absorptiometry database at King Faisal Specialist Hospital and Research Centre, resulting in an AAM distribution for 391 postmenopausal women with natural menopause. This was preprocessed using a Fast Fourier Transform 0.15 cycles/year low-pass filter, eliminating last-digit-preference errors and high frequency noise, and facilitating quantitative comparison with other published results. Results: Mean AAM was 48.94 years (S.E. 0.290 years) with a median of 50 years (25th/75th percentiles: 45 and 53 years, respectively). The AAM distribution was described by a quadruple-Gaussian curve with a major peak at almost 51 years and minor peaks at approximately 36, 44 and 59 years. Although both the central peaks were similar to that observed in other populations (UK, USA and Finland), the early menopause peak at 36 years was larger. The peak over 55 years may be unique to the Kingdom of Saudi Arabia. It may reflect local cultural and childbearing practices. Conclusions: Although the median menopause age and general shape of the AAM distribution in Saudi Arabia appear similar to that observed in the West, the parameters governing the distribution are different, and there is evidence that it may have a unique fourth peak.