IntroductionThe greatest prevalence of back symptoms and sciatica in the Finnish female population occurs just after menopause, at between 55 and 64 years, and it starts to increase between 45 and 54 years of age [21]. In an epidemiological study, increased risk of back symptoms without known etiology exists within those who have had premature menopause [1]. Spinal mobility is one aspect of back performance that has been shown by cross-sectional studies to decrease with age and spinal degeneration [5,7,29,31,37,42,45,47]. The fibrocartilaginous intervertebral discs between the vertebrae allow the spine to bend and twist with hydraulic properties. The discs, ligaments, and zygoapophyseal joints, and especially the collagen in them, restrict spinal mobility [13,23,47]. Human intervertebral discs consist of eight different types of collagen [23,47]. Collagen type I is predominant in the outer annulus fibrosus and collagen type II in the inner layers [11,47]. Collagen type I is thought to provide the tensile properties of the annulus fibrosus and other tissues [23]. The tensile properties of collagen depend largely upon the formation of intermolecular cross-links between the constituent molecules [13]. The changes in the proportions of the different collagen types in the spine along with aging and the Abstract The purpose of this study was to examine the influence of estrogen-progestin replacement therapy and exercise on the lumbar spine mobility and back symptoms of early postmenopausal women. The population sample consisted of 78 healthy, 49-to 55-year-old women, 0.5-5 years after menopause, who were randomized into three groups, two receiving different protocols of estradiol valerate combined with medroxyprogesterone acetate replacement therapy, and the third group a placebo. These groups were then randomized into exercise and control cases and monitored for 2 years. The mobility of the lumbar spine was measured and symptoms investigated using the Million and Oswestry pain and disability questionnaires and pain drawings at the baseline and after 1 and 2 years. During the followup, the mobility of the lumbar spine decreased in all six groups. The decrease was most evident in those who had been the most flexible at baseline (P < 0.0001). The decrease was less notable in the hormone replacement therapy groups than in the control group. When the replacement therapy groups were pooled together, the difference was significant at a P < 0.05 level. No difference was seen between the hormone combinations. The exercise intervention was insufficient to influence lumbar spine mobility. Only sporadic cases of back symptoms appeared and disappeared among the subjects during the follow-up, and no preventive or aggravating effects of hormone replacement therapy or the exercise program on symptoms were detected.
