Subjects

Subjects were recruited from the Raleigh/Durham/Chapel Hill areas in North Carolina through a community PCOS support group and by word of mouth. After meeting initial eligibility criteria by phone, including replying "yes" to the question, "Have you been told by your health care provider that you have PCOS?," subjects were asked to attend a screening visit for a medical history and physical exam. Informed consent approved by the local Institutional Review Board was obtained. Baseline blood tests were also performed at the screening visit. There were no monetary incentives for participation.

Inclusion/exclusion criteria

The inclusion criteria were age 18–45 years, diagnosis suggestive of PCOS based on history of chronic anovulation and/or hyperandrogenemia, no other serious medical condition requiring medical supervision, body mass index (BMI) greater than or equal to 27 kg/m2, willingness to use acceptable contraception, and a desire to lose weight. Exclusion criteria included pregnancy, nursing or positive pregnancy test during screening period, and rapid progression of hyperandrogenic signs and symptoms.

Intervention

Subjects received an intensive group education program during monthly group meetings held every other week throughout the 6-month study period. During the first group meeting, subjects were instructed on both the rationale and implementation of the dietary intervention via use of a LCKD diet book and handouts containing suggestions on choice of appropriate foods.[18] Subjects were then instructed to begin the diet the following day. During follow-up group meetings, study outcome measures were obtained, and continued dietary counseling, adjustment of individual medications, supportive counseling, sharing of food choices, and review of urinary ketones were performed. The duration of each meeting was approximately 1 hour.

Subjects were instructed to follow the LCKD, consisting of fewer than 20 grams of carbohydrate per day, as tolerated throughout the 6-month study period. The diet includes unlimited consumption of animal foods (meat, chicken, turkey, other fowl, fish, shellfish), prepared and fresh cheeses (up to 4 and 2 ounces per day, respectively), unlimited eggs, salad vegetables (2 cupfuls per day), and low carbohydrate vegetables (1 cupful per day). Subjects were strongly encouraged to drink at least six 8-ounce glasses of permitted fluids per day, and discouraged to drink caffeine and alcohol. Subjects were also encouraged to take one multivitamin per day and to exercise at least three times per week on their own, although this was not mandatory.

Outcome measures

At the screening visit, baseline variables included age, gender, race, height, weight, prior use of weight loss programs, blood pressure, and laboratory tests. During the study, dietary adherence was measured by food records, self-report, and urinary ketones. Five-day food records for the days immediately preceding an upcoming group meeting were collected at baseline and weeks 2, 4, 12, and 24. Most dieters not on an LCKD do not have urinary ketones. As the intake of fewer than 20 g/day of carbohydrate typically results in urinary excretion of ketones, the presence of ketonuria was used to verify dietary adherence. (Urinary ketones were measured on a scale of 0="none" to 5="Large 160.")

Body weight was measured at each visit on the same scale with the subject wearing light clothing but with shoes and socks removed. (Tanita Model TBF-300A, Tanita Corp., Arlington Heights, Illinois) At all return visits, blood pressure was measured in the nondominant arm, using an automated digital cuff after sitting for 3 minutes (Omron Model HEM-725C, Omron Corp., Vernon Hills, Illinois). Two measurements were taken at each visit and averaged for the analysis. Blood tests were taken at baseline, 10, and 24 weeks after a 12 hour fast. Serum total and free testosterone were measured by immunoassay and equilibrium ultrafiltration; insulin by chemiluminescent immunometric assay.

A self-administered PCOS-specific questionnaire was completed by each subject during baseline and during each follow-up visit in order to monitor for changes in subjective symptoms related to PCOS.[19, 20] The PCOS-Q includes 25 items from five health related quality of life domains: emotions (7 items), hair growth (5 items), body weight (5 items), infertility (5 items), and menstruation (4 items). Each item is rated on a seven-point scale in which a score of 7 indicates no problems or difficulties and a 1 indicates maximum impairment on that item. The mean score of all items in a domain provides a domain score for each subject.

Statistical analyses

Because this pilot study used a "pre-post" design and the comparison of interest was the percent change from baseline to 24 weeks, a two-tailed paired t test was used to test for statistical significance of outcome variables. A p value of ≤ 0.05 was used for statistical significance.