Comparison of dietary and physical activity behaviors in women with and without polycystic ovary syndrome: a systematic review and meta-analysis of 39 471 women

Abstract

Background: Lifestyle (dietary and/or physical activity [PA]) modification is recommended as first-line therapy to manage polycystic ovary syndrome (PCOS). Current recommendations are based on healthy lifestyle practices for the general public since evidence for unique lifestyle approaches in PCOS is limited and low quality.

Objective and rationale: We aimed to synthesize evidence on dietary and PA behaviors between women with PCOS and those without PCOS. Primary outcomes were overall diet quality, total energy intake and total PA, and secondary outcomes included macronutrients, micronutrients, food groups, foods, glycemic indices, sedentary time and sitting levels. We conducted this work to identify any unique lifestyle behaviors in women with PCOS that could underlie the propensity of weight gain and obesity in PCOS and be targeted for precision nutrition and PA interventions. These findings could be used to inform future practice recommendations and research that more effectively address complications (weight gain, obesity, diabetes, infertility, cardiovascular disease and mental health) in this high-risk population.

Search methods: Databases of MEDLINE, Web of Science, Scopus and CINAHL were searched until 15 February 2022 to identify observational studies documenting dietary and PA behaviors between women with PCOS and without PCOS (Controls). Studies on children, adolescents (<18 years), pregnant or menopausal-aged women (>50 years) were excluded. Data were pooled by random-effects models and expressed as (standardized) mean differences (MD) and 95% CIs. The risk of bias was assessed by the Newcastle-Ottawa scale (NOS).

Outcomes: Fifty-four studies (N = 39 471 participants; [n = 8736 PCOS; 30 735 Controls]) were eligible (96%; [52/54] NOS scores ≥ 7). Women with PCOS had higher cholesterol (MD: 12.78, 95% CI: 1.48 to 24.08 mg/day; P = 0.03; I2 = 19%), lower magnesium (MD: -21.46, 95% CI: -41.03 to -1.91 mg/day; P = 0.03; I2 = 76%), and a tendency for lower zinc (MD: -1.08, 95% CI: -2.19 to -0.03 mg/day; P = 0.05; I2 = 96%) intake, despite lower alcohol consumption (MD: -0.95, 95% CI: -1.67 to 0.22 g/day; P = 0.02; I2 = 0%) versus Controls. Also, women with PCOS had lower total PA (standardized mean difference: -0.38, 95% CI: -0.72 to 0.03; P = 0.03; I2 = 98%). Conversely, energy, macronutrients (carbohydrate, fat, protein, fiber), micronutrients (folic acid, iron, calcium, sodium), glycemic index and glycemic load were similar (all: P ≥ 0.06). Most eligible studies reported lower total adherence to healthy eating patterns or poorer consumption of major food groups (grains, fruits, vegetables, proteins, seeds, nuts, dairy) in women with PCOS, as described narratively since variable study methodology did not permit meta-analyses.

Wider implications: Collective evidence supports that women with PCOS have a lower overall diet quality, poorer dietary intakes (higher cholesterol, lower magnesium and zinc) and lower total PA, despite lower alcohol consumption versus those without PCOS. Considerable heterogeneity among studies reinforces the need for research to address any relative contributions of other factors (e.g. genetic, metabolic or sociodemographic) to the observed differences. These clarifications may contribute to future evidence-based guideline recommendations on monitoring and managing PCOS in the era of precision lifestyle medicine.

Keywords: PCOS; exercise; lifestyle; nutrition; obesity; polycystic ovary syndrome; reproduction.

Figure 1.

PRISMA 2020 flow diagram for new systematic reviews, including searches of databases, registers and other sources.

Figure 2.

Forest plot for energy intake in women with and without PCOS with effect estimate expressed as kcal/day. MD, mean difference.

Figure 3.

Forest plot for total physical activity level in women with and without PCOS. SMD, standardized mean difference.

Figure 4.

Forest plots for carbohydrate intake in women with and without PCOS. (A) Total carbohydrate intake. (B) Added sugar expressed in g/day. MD, mean difference; SMD, standardized mean difference.

Figure 5.

Forest plots for fat intake in women with and without PCOS. (A, total fat; B, saturated fatty acids [SFA]; C, monounsaturated fatty acids [MUFA]; D, polyunsaturated fatty acids [PUFA]; E, cholesterol) with cholesterol expressed as mg/day. SMD, standard mean difference.

Figure 5.

Continued

Figure 6.

Forest plots for protein, fiber and alcohol intake in women with and without PCOS. (A) protein intake; (B) fiber intake expressed as g/day; and (C) alcohol intake expressed as g/day. MD, mean difference; SMD, standardized mean difference.

Figure 7.

Forest plots for micronutrient intake in women with and without PCOS. (A) Folic acid intake expressed as µg/day; (B) vitamin D intake expressed as µg/day; (C) iron intake expressed as mg/day; (D) calcium intake expressed as mg/day; (E) magnesium intake expressed as mg/day; (F) zinc intake expressed as mg/day; and (G) sodium intake expressed as mg/day. MD, mean difference.

Figure 7.

Continued

Figure 8.

Forest plots for status of dietary glycemic indices in women with and without PCOS. (A) glycemic index and (B) glycemic load. MD, mean difference.