Relationship between HEI-components
Correlations between the HEI component and total scores were evaluated to determine the amount of unique information contained in each HEI-components. The total HEI score had moderate-to low correlations with the individual HEI-component scores, but the HEI-components showed many significant correlations (P < 0.05, r > 0.1; n = 378; Supplemental Table 3). Of those, strong correlations were seen between ‘total fruits’ and ‘whole fruits’ (r = 0.87) and ‘fatty acids’ and ‘saturated fats’ (r = 0.73). Moderate correlations were seen between ‘greens and beans’ and both ‘total vegetables’ (r = 0.63) and ‘seafood and plant proteins’ (r = 0.45), ‘total vegetables’ and ‘added sugars’ (r = 0.43), and between ‘dairy’ and ‘fatty acids’ (r = − 0.42), and between ‘total protein’ and ‘seafood and plant proteins’ (r = 0.40). All other observed correlations were weak (r < 0.4).
Dietary differences with age, sex and cardiometabolic risk factors
Overall, the total HEI scores were similar between sexes, and were higher (P < 0.01) in those 50 to 65 y compared to those 18 to 49 y, regardless of CMDrf group association. However, other sex and age associations with CMDrfs differed. A higher total-HEI score was associated with lower HOMA in women but lower BMI in men. In addition, a higher total-HEI score was associated with lower BMI and HOMA in the young and middle-aged groups, but only a lower BMI in older individuals.
Numerous sex-dependent differences in HEI-components were detected. Women had higher scores for ‘total vegetables’ and ‘whole fruit’ (P < 0.05) and a lower ‘saturated fat’ score (P = 0.03) than men (Supplemental Table 2). In women, higher scores also approached significance for ‘total fruits’ (P = 0.07), ‘dairy’ (P = 0.09), and ‘refined grain’ (P = 0.1), as did lower scores for ‘total protein’ (P = 0.06) and ‘added sugars’ (P = 0.06). Men aged 18 to 33 y had lower ‘total fruit’ and ‘whole fruit’ scores than other age categories (P < 0.01), while women 50 to 65 y had higher ‘refined grain’ scores and men 50 to 65 y had higher ‘saturated fats’ scores than other age groups (P < 0.05). Women and men 50 to 65 had higher ‘whole grain’ and ‘sodium’ scores than other age groups (P < 0.01). Scores for ‘greens and beans’, ‘seafood and plant proteins’, and ‘fatty acids’ showed no differences between sex or age.
CMDrf group classification
Of the 393 participants, 286 were stratified into the high CMDrf group with either 1 (n = 71; n = 62), 2 (n = 39; n = 31), or 3+ (n = 47; n = 36) risk factors for women and men, respectively. Notably participant selection was stratified to provide balanced sex and age coverage of normal, overweight and obese participants, thereby may over sample the high CMDrf group from the geographic area. Regardless, only 25% (n = 99) of participants had BMI > 25 kg/m2 as a unique risk factor. Of the 31 participants without clinical blood measures, 25 were classified in the high CMDrf group by BMI. Of the participants with BMI and clinical blood measurements, only 5% were classified as high risk with BMI < 25 kg/m2. Therefore, of the 6 participants classified in low CMDrf group based on BMI without supporting clinical measurements, it is estimated that 2 could be misclassified. This would represent a misclassification rate of 0.5% and was deemed acceptable. With these caveats, the phenotyping cohort was stratified into low- (n = 107; ~ 27%) and high (n = 286; ~ 73%) CMDrf groups that differed (P < 0.01) in BMI, HDLc, triglycerides (TG) and HOMA (Table 1, Supplemental Table 4). Sex differences in the prevalence of overweight and obese conditions were not significant. In the low CMDrf group, participants aged between 50 to 65 y had higher HDLc (P < 0.01) than 18 to 49 y olds (72 vs 63 mg/dL). TG was not higher (P = 0.10) in the high CMDrf group in participants aged between 34 to 65 y compared to 18 to 33 y olds (115 vs 90 mg/dL). Only 15 participants were tobacco-users and were not associated with specific CMDrf groups.
Dietary score differences between CMDrf groups
Of the 393 participants, HEI scores were calculated for 378 who completed two or three 24-h recalls. The high CMDrf group had lower total HEI-score than the low CMDrf group (total HEI-score 60 vs. 66, respectively; P < 0.01). Similarly, the high CMDrf group had lower scores for ‘total fruits’, ‘whole fruits’, ‘total vegetables’, ‘greens and beans’, ‘seafood and plant proteins’, ‘fatty acids’, and ‘saturated fats’.
Sex-specific differences between high and low CMDrf groups in HEI-components of ‘total fruits’, ‘whole fruits’, ‘total vegetables’, ‘greens and beans’, ‘dairy’, ‘seafood and plant proteins’, ‘sodium’, ‘fatty acids’, and ‘saturated fats’ scores were observed (P < 0.05; Fig. 2). In women, the high CMDrf group had lower ‘total fruits’, ‘whole fruits’, ‘seafood and plant proteins’, ‘total-vegetables’, ‘sodium’, ‘fatty acids’, and ‘saturated fats’ and higher ‘dairy’ scores. In contrast, men in the high CMDrf group only showed lower ‘total vegetables’ and ‘greens and beans’ scores. ‘Whole grain’, ‘refined grain’, and ‘added sugars’ did not differ between CMDrf groups.
Diet patterns by sex and age for low and high cardiometabolic risk factors (CMDrf). Radar graph depicting dietary patterns of quality according to Healthy Eating Index-2015 (HEI) for a low (n = 106) and high (n = 272) CMDrf in women and men by age in a cross-sectional study. HEI-component scores are expressed as a percentage of their maximum score, with scores increasing with diet quality. Each point represents the mean ± standard error of means. Diet components in bold-italic are recommended to be eaten in moderation. * The symbol represents the HEI-components included in the predicted CMDrf models. Abbreviation of HEI-components are total-vegetables (ToVeg); saturated fat (satFat); total protein (ToPro); refined-grains (rGr); ‘fatty acids’ (FAs); ‘greens and beans’ (G&B); whole-grain (wGr) total-fruit (ToFru); sea-food and plants (S&PPro); whole-fruits (WFru); ‘added sugars’ (AdSug; n = 3); ‘sodium’ (Sod)
HEI-component-based prediction of CMD-risk factor presence
As multiple sex by age differences in HEI-component scores were identified (Supplemental Table 2), models were built to assess age x sex categories (Supplemental Tables 5, 6, and 7). HEI-component-based CMDrf group prediction was excellent for women, and good for men across age groups. (Table 2, Supplemental Fig. 2). The frequency of HEI-component inclusion by the stepwise discriminant analysis in the six age x sex models were ‘dairy’ = ‘total vegetables’ = ‘saturated fats’ (n = 6; 100%) > ‘greens and beans’ = ‘total proteins’ = ‘refined grain’s = ‘fatty acids’ (n =5; 83%) > ‘whole grain’s = ‘total fruits’ = ‘seafood and plant proteins’ (n = 4; 66%) > ‘whole fruits’ = ‘added sugars’ = ‘sodium’ (n = 3; 50%) (Supplemental Table 8).
The dietary component CMDrf group classification accuracy showed high sensitivity (91% accuracy) within sex and age (Table 3). However, model specificity was age dependent, increasing with age: younger-age (78%) < middle-age (85%) < older-age (> 90%). The predicted vs a priori CMDrf misclassification rate was only 10% overall, ranging from 8 to 14% across sex and age groups, with misclassification highest in the youngest groups (Supplemental Table 9). Similarly, these diet-based models for women classified the independent group of overweight to obese women from the controlled feeding intervention with 100, 87 and 100% sensitivity for young, mid and older age groups, respectively. Except for lower ‘fatty acids’ scores in the controlled feeding intervention (P = 0.04), HEI-components were similar in high CMD-risk groups across the two studies (Supplemental Table 10).
‘Dairy’, ‘total vegetables’ and ‘saturated fats’ were the HEI-components common to all diet-based CMDrf prediction models across sex and age. The average HEI-component profiles of the predicted CMD-risk groups are shown in Supplemental Table 11 and are parallel to the findings reported in Fig. 2.
Risk factor patterns in diet-predicted high vs low CMDrf groups
Finally, we evaluated how HEI-component based CMDrf group prediction segregated the CMD risk factors used for stratification and other clinical parameters associated with cardiometabolic health. As expected, BMI, fasting insulin, and HOMA were higher in both sexes across all age categories in the high CMDrf group (P < 0.05; Table 4). Postprandial insulin resistance was also higher in high CMDrf groups in both sexes (P < 0.01), but was higher in men than women (P < 0.01). The lipid profile of the predicted high CMDrf group was characterized by a lower HDLc and higher total cholesterol, LDL cholesterol (LDLc), and fasting TG in both sexes at all ages (P < 0.05). The HDLc concentration increased with age in the low CMDrf group in women (68, 72, 82 mg/dL respectively for age category), but not in men, while remaining low in the high CMDrf group across age and sex (P = 0.01; Table 4). For participants over 30y of age, the average Framingham risk (%) was also higher (P = 0.03) in 5.5% in the high compared to 4% in the low CMDrf groups, but sex by risk interactions were not significant (P = 0.07).
