A full depiction of the sample, overall and stratified by sex, is shown in Fig. 2. Distribution of sex, race, and ethnicity are shown in Table 1. Tentative eligibility was examined in 14,817 people. Among them, 2796 (18.9% of 14,817) were eligible to attend an info session. However, the sex of 118 of them was unknown, and hence excluded from all analyses. Of 1717 (61.4% of 2796) people (with known sex) who attended an info session, 1142 (66.5% of 1717) attended a baseline examination. From this, 653 (57.2% of 1142) were deemed eligible for the trial, and 618 (94.6% of 653) were randomized. Significant results discussed below are summarized in Tables 2 and 3 for males and females, respectively.

Fig. 2

Results of the ELM screening process and samples used for each analysis

Table 1 Participant characteristicsTable 2 Significant predictors of male participationTable 3 Significant predictors of female participationInformation session attendance (analysis 1)

Among 769 males eligible to attend the information session, there were 448 (58.3%) who attended and 321 (41.7%) who did not. Among 1909 females, there were 1269 (66.5%) who attended and 640 (33.5%) who did not. In the unadjusted models, three factors were positively associated with attendance in only male respondents: (i) self-reported fasting glucose between 100 and 125 mg/dL, which is the state of prediabetes, compared to below 100 mg/dL (OR = 1.69, p = 0.005), (ii) 10-point self-efficacy Likert scale item asking, “How confident are you that you can be or can work up to be physically active for at least 30 min on most days?” (OR = 1.24, p = 0.002), and (iii) presence of a major food allergy or dietary preference (OR = 1.97, p = 0.03). In the adjusted model controlling for all significant predictors from the unadjusted analyses, other chronic illness (OR = 1.66, p = 0.02), confidence in being active (OR = 1.29, p = 0.0007), and Black race compared to White (OR = 0.51, p = 0.002) remained significant independent predictors of attendance for males.

Common to both sexes, race (coded as White, Black, or other) and self-reported presence of other chronic illness or health problems (coded as yes or no) were significantly associated with attending an info session. Unique to female respondents, a 10-point Likert scale asking, “How willing and able are you to make changes to your current diet?” was significant (OR = 1.11, p = 0.03). In the adjusted model, willingness to change diet (OR = 1.12, p = 0.02) and Black race compared to White (OR = 0.68, p = 0.0007) remained significant.

Baseline examination attendance (analysis 2)

Among 448 males who attended the information session and were invited to complete the baseline examination, 293 (65.4%) attended and 155 (34.6%) did not. Among 1269 females, 849 (66.9%) attended and 420 (33.1%) did not. Hispanic ethnicity was significantly associated with lower odds (OR = 0.51, p = 0.04) of attendance for males. Self-reported diagnosis of asthma was positively associated with female attendance (OR = 1.55, p = 0.01). No other factor was statistically significant for either sex. As there was only one significant predictor, no adjusted analyses were conducted.

Trial enrollment compared to respondents eligible for randomization but not interested (analysis 3)

Of the 1142 who attended a baseline examination, 489 were ineligible for the trial (due to incomplete baseline, no MetS, etc.), 618 (94.6%; 150 males, 468 females) were randomized, and 35 (5.4%; 9 males, 26 females) were eligible to be randomized but not interested in the trial. The purpose of analysis 3 was to compare the latter two categories. However, due to the very small number of people who were eligible but not interested (N = 35), no analyses were conducted as any evidence from it would likely not be robust.

Trial enrollment compared to respondent not interested at any point in the recruitment process (analysis 4)

The 618 randomized participants were compared to the combined group consisting of those who did not attend an info session, did not attend baseline examination, were eligible to be randomized but were not interested, and indicated they were not interested in the middle of baseline examination (n = 1630, 499 males, 1131 females). Unique to male respondents, self-reported A1c between 5.7 and 6.4% (OR = 1.57, p = 0.03), current order of fibrates medication (OR = 2.34, p = 0.01), fasting glucose between 100 and 125 mg/dL (OR = 1.68, p = 0.03), and triglycerides over 150 mg/dL (OR = 1.95, p = 0.003) were all positively associated with trial enrollment. Current order of fibrates and triglycerides remained as significant predictors in the final adjusted model.

Only race was significant in both sexes, with Black respondents less likely to enroll compared to White respondents (OR = 0.41, p = 0.0032 for males; OR = 0.55, p < 0.0001 for females). For females, willingness to make changes to their current diet (OR = 1.15, p = 0.01) and presence of other chronic illnesses (OR = 1.30, p = 0.03) were uniquely associated to trial enrollment. Willingness to change diet (OR = 1.17, p = 0.008) and Black race (OR = 0.55, p < 0.0001) remained significant in the adjusted model.

The proportion of males and females who chose to move forward to the subsequent step in the recruitment process were compared using chi-squared tests. No significant differences were found in proportions of males and females for baseline attendance or trial enrollment, meaning qualifying males and females were equally likely to attend baseline assessments and enroll in the trial. However, there was a significant difference in proportions (58.3% in males vs. 66.5% females; p < 0.001) attending an info session after being tentatively eligible.