By Alexa Allen, MD
Editor’s Note: This study features a randomized comparison of the influence of dietary management and/or physical exercise on ovarian function and metabolic parameters in overweight women with polycystic ovary syndrome. It was summarized by Alexa Allen while on the FACTS elective, Fertility Awareness-Based Methods for Family Planning and Women’s Health. Lifestyle interventions, including diet and exercise, significantly improve metabolic health and restore ovulation in overweight women with PCOS. Women with PCOS face up to a three times higher risk of developing type 2 diabetes by age 40 compared to those without the condition, making early, regular screening and lifestyle adjustments critical. For a deeper look at how nutrition and physical activity affect fertility, register for Part G of our CME course, Lifestyle and Fertility.
Introduction
Polycystic ovary syndrome (PCOS) is an endocrine disorder that is a common cause of menstrual dysfunction and infertility among women of reproductive age. Additionally, PCOS is associated with clinical features that are known risk factors for both cardiovascular disease and type 2 diabetes, including obesity, increased abdominal fat, and insulin resistance. [1] Infertility or subfertility is an important concern among women of reproductive age with PCOS, and therefore, developing treatment strategies to improve reproductive function in these women is an area of significant interest. This study by Nybacka et al. describes a randomized comparison that was designed to better understand the influence of dietary and exercise interventions on ovarian function, metabolic status, and endocrine parameters in overweight women with PCOS. [2]
“Polycystic ovary syndrome (PCOS), an endocrine disorder that is a common cause of menstrual dysfunction and infertility …is (also) … associated with clinical features that are known risk factors for both cardiovascular disease and type 2 diabetes.”
Methodology
The patients in this study were recruited through clinical referrals and local newspaper advertisements and were then screened based on pre-determined criteria. Qualifications included a formal diagnosis of PCOS based on the Rotterdam Consensus criteria, including ages 18 to 40 and body mass index (BMI) greater than 27 kg/m2, among others. A total of 57 women were enrolled in the study based on the defined criteria and randomly assigned to one of the following intervention groups: dietary management, physical exercise, or combined dietary management and exercise. The diets for the dietary and combined groups were determined on an individual basis for each participant under the guidance and supervision of a dietitian. Similarly, the exercise program was overseen by a physical therapist and tailored to each participant.
The interventions for each group lasted for four months with each subject completing monthly visits. The study assessed body composition, metabolic status, endocrinologic parameters, and ovarian function through physical exams, ultrasounds, dual energy x-ray absorptiometry, and laboratory tests that were completed immediately before the study, after four months of intervention, and at a long-term follow-up at least one year after program completion.
Results
Of the 57 subjects initially recruited for the study, 14 were excluded or dropped out for various medical or personal reasons. After the 4-month intervention, subjects in the dietary and combined groups reported a significant reduction in caloric intake. There was also a reduction in the self-reported caloric intake in the exercise group, but this was less than that seen in the other groups. Participants also tracked the number of steps taken per day, and a significant increase in steps was seen in the exercise and combined groups but not in the dietary group. In contrast, weight loss was greatest in the dietary and combined groups compared to the exercise group. There was also a significant reduction in total body fat percentage seen only in the dietary group. Overall, there was a reduction in BMI seen among all study groups with no significant difference between groups.
More than two-thirds of participants (30 of the 43 subjects) across all three intervention groups showed improvement in cycle regularity from either oligomenorrhea or amenorrhea to regular menstruation. Ovulation was also evaluated and was detected in 15 of the 43 women with no significant differences seen between groups.
“More than two-thirds of participants … across all three intervention groups showed improvement in cycle regularity from either oligomenorrhea or amenorrhea to regular menstruation.”
Endocrinologic and metabolic parameters – including total testosterone, insulin, glucose, and insulin-like growth factor (IGF-I) and insulin-like growth factor binding protein 1 (IGFBP-1) levels – were also evaluated. A lower testosterone level before treatment was the strongest predictor of an improved menstrual pattern, and a higher serum IGFBP-1 level after treatment was the most significant predictor of ovulation after stepwise regression.
Long-term follow-up results were obtained for seven patients from each group for a total of 21 patients, though there were attempts to reach out to all study participants. Results showed an overall mean decrease in BMI after termination of the program for the dietary, exercise and combined groups. The menstrual status was found to be unchanged or improved in 15 of the 17 women who were not using hormonal contraception from the group with 11 women exhibiting regular mensuration. The study found that programmatic lifestyle interventions improved menstrual regularity in 69% of participants, with ovulation confirmed in 34% of cases.
Discussion
With PCOS estimated to affect 5-10% of women of reproductive age, the impact of this disorder on menstrual function, fertility, cardiovascular disease, and type 2 diabetes risk makes it an important area of focus. [3] The results of Nybacka et al.’s study [2] demonstrate that dietary and exercise interventions alone and in combination are effective at improving ovarian function and reproductive potential in women who are overweight and have PCOS. These interventions maintained over the 4-month study period led to resumption of regular menstruation in two-thirds of the subjects and confirmed ovulation in one-third of the patients, with benefits also seen beyond at least one year following the intervention. These improvements were observed alongside reductions in weight, BMI, and other body composition parameters across all groups, although only minor weight loss was observed in the exercise-only group.
“The results of this study demonstrate that dietary and exercise interventions … led to resumption of regular menstruation in two-thirds of the subjects and confirmed ovulation in one-third of the patients, with benefits also seen beyond at least one year following the intervention.”
The strengths of this study include the prospective randomized design and the long-term follow-up component which allowed the researchers to better understand the ongoing impact of the intervention. Some limitations of this study include a small sample size and a relatively high dropout rate. However, the researchers attempted to address the limitation of the small sample size with a power calculation.
While this study supports the importance of lifestyle modifications as the first-line treatment for PCOS, it is important to consider the challenges associated with making behavior modifications related to diet, exercise, and weight management. Behavioral therapy literature suggests that individuals have significant difficulty maintaining healthy behavior changes, with reports estimating premature dropout rates of 30 to 60%. [4] Additionally, programs focusing on weight management or lifestyle intervention targeting diet and exercise without weight change objectives have shown patterns of good initial adherence with a gradual reduction in the maintenance of behavior change that declines steadily as time passes. [4]
The individualized and supportive dietary and exercise programs used in this study may represent one potential solution to addressing the challenges associated with behavior modification and numerous factors, including economic, societal, cultural, and psychological factors, that have been found to influence adherence to and maintenance of lifestyle changes. Further research and investigation are still needed in this area to better understand and address these challenges.
References
[1] Apridonidze T, Essah PA, Iuorno MJ, Nestler JE. Prevalence and characteristics of the metabolic syndrome in women with polycystic ovary syndrome. Obstetrical & Gynecological Survey. 2005;60(9):589-591. doi:10.1097/01.ogx.0000175799.50780.34.
[2] Nybacka Å, Carlström K, Ståhle A, Nyrén S, Hellström PM, Hirschberg AL. Randomized comparison of the influence of dietary management and/or physical exercise on ovarian function and metabolic parameters in overweight women with polycystic ovary syndrome. Fertility and Sterility. 2011;96(6):1508-1513. doi:10.1016/j.fertnstert.2011.09.006.
[3] Azziz R, Woods KS, Reyna R, Key TJ, Knochenhauer ES, Yildiz BO. The prevalence and features of the polycystic ovary syndrome in an unselected population. The Journal of Clinical Endocrinology & Metabolism. 2004;89(6):2745-2749. doi:10.1210/jc.2003-032046.
[4] Middleton KR, Anton SD, Perri MG. Long-Term Adherence to Health Behavior Change. American Journal of Lifestyle Medicine. 2013;7(6):395-404. doi:10.1177/155982761348886.
ABOUT THE AUTHOR
Dr. Alexa Allen is a fourth-year resident physician in Obstetrics and Gynecology at the University of Arizona College of Medicine – Phoenix. She completed both parts of the FACTS electives as a fourth-year medical student at the University of Nevada, Reno School of Medicine with the goal of learning more about fertility awareness-based methods (FABMs) and has continued to use the knowledge that she gained from these experiences to help educate and empower her patients.
