To begin, some definitions may be helpful.
“Menopause” refers to the time of life when the ovaries stop making the female hormones, estrogen and progesterone. While scientists once thought that this occurred suddenly, perhaps over a month or two, now we know that menopause occurs gradually, lending to the term “perimenopausal transition.” This process takes place over a two to five year period. During that time, the amount of estrogen made in the ovaries shifts back and forth, from normal amounts to high amounts to none at all.
“Hormone replacement therapy” includes estrogen and progesterone. Women who have had hysterectomies are prescribed progesterone to maintain a healthy uterine lining. Those who have not had a hysterectomy do not need to take progesterone.
“Natural and synthetic hormones” usually refer to the source that the hormone supplement is derived from. Natural hormones have not been shown to produce greater benefits or fewer side effects than synthetic ones and the amount of hormone released may be less consistent.
Weight gain does not seem to be different when natural progesterone or synthetic progesterone-like medications are used. Though not inevitable, most women gain weight after menopause. It is likely to be more a function of age and activity than hormones. Both men and women tend to gain weight as we age, but weight gain is accelerated in the early menopausal years. Studies have shown that even without estrogen, women in early menopause can expect an increase of 4-5 pounds per year (as compared to a national average of 1-2 pounds before menopause).
Hormone therapy seems to have little impact on overall weight gain. In most studies, women who take estrogen gain the same 4-5 pounds as those who avoid postmenopausal replacement. Neither do estrogen or progesterone replacement medications increase appetite. The type of hormone therapy doesn’t seem to have an impact on the amount of weight gained or the distribution of fat.
In the largest study of menopause, hormones and weight change, (3286 women at the start; 671 women aged 65 through 94 years at the conclusion) and longest ever (over 15 years), the following findings were reported:
• women taking hormones tended to be leaner than nonusers when first given estrogen
• but after 15 or more years of hormone replacement, they tended to catch up with the weight of nonusers.
• the difference in weight change between baseline and follow-up in both intermittent and continuous users vs nonusers was only half a kilogram (1 pound).
• both intermittent and continuous hormone users were more likely to have made dietary and lifestyle changes to promote health since 1975, but adjustment for these differences did not alter the results.
• in addition to weight, some studies suggest estrogen replacement may have an effect on the distribution of fat. Women who take estrogen may be more likely to hold fat in the hips and thighs, the “female” pattern. As in nearly every other aspect of medicine, there are exceptions to this general rule.
• This lower waist-hip ratio, or “gynoid” fat distribution, carries less risk for diabetes, heart disease, and cardiovascular risk factors than that associated with an android or upper body distribution. However, others reported no independent association of estrogen with waist-hip ratio.
• The authors concluded, “the long-term effect of estrogen use on body fat distribution, if any, is likely to be relatively small.”
• Since there were no significant differences in rates of diabetes or use of diuretics (water pills), or steroids, it is also unlikely that these conditions masked an association between hormone use and obesity.
Besides being the largest and longest study, the reported results were consistent with others who also found no difference in weight between estrogen users and nonusers after 1 year of follow-up, a 10-year clinical trial, and from a large 3-year randomized clinical trial (PEPI study).
It is important to add that, in the Lindora clinics, we do not see a significant difference in rates of weight loss or success at maintaining weight among those taking hormones or not. In fact, some of our most successful patients have been on hormones. In one study conducted among the 30 clinics, the age group most likely to lose and maintain weight was greater than 75 years old. There was not a big difference in how well women did compared to men or how well women on hormones did compared to those not on them. In looking more closely at this group, we found that many of the 75-year olds had health and quality of life issues related to their weight. They tended to be very highly motivated, as evidenced by their consistency and perseverance in following the program. As a group, they made more visits per week, continued maintenance longer than those in other age groups, and followed through with recommendations regarding walking, recording daily foods, and were more often in ketosis.
The take-home message should be that, whether taking hormones or not, weight control is challenging but possible. It may take longer, or prove more difficult for people of one age group, gender, or condition than another but, in the end, persistence and compliance win out.
For reprint requests of the largest study of hormones and weight, check the library or internet for: Title: Long-term postmenopausal hormone use, obesity, and fat distribution in older women. Authors: Donna Kritz-Silverstein Elizabeth Barrett-Connor Journal: JAMA, The Journal of the American Medical Association (JAMA. 1996;275:46-49) or write to: Department of Family and Preventive Medicine, 9500 Gilman Dr, 0607, La Jolla, CA 92093-0607 (Dr Barrett-Connor).