TABLE 3.
Egg, cholesterol, choline, and betaine consumption, adjusted for intake of different nutrients, and HRs and 95% CIs for incident diabetes in the Women's Health Initiative1
| Consumption quintiles2 | ||||||
|---|---|---|---|---|---|---|
| Adjustment variables | 13 | 2 | 3 | 4 | 5 | P-linear4 |
| Exposure: egg consumption | ||||||
| Cases/women5 | 887/1459 | 1054/9690 | 946/8476 | 1132/9388 | 1457/10,215 | |
| Total cholesterol | 1.00 | 0.98 (0.90, 1.08) | 0.99 (0.89, 1.09) | 1.01 (0.91, 1.12) | 1.09 (0.96, 1.22) | 0.07 |
| Total choline | 1.00 | 1.00 (0.91, 1.09) | 1.01 (0.92, 1.11) | 1.06 (0.97, 1.16) | 1.17 (1.07, 1.29) | <0.0001 |
| Total cholesterol and total choline | 1.00 | 0.98 (0.90, 1.08) | 0.98 (0.89, 1.09) | 1.00 (0.90, 1.12) | 1.08 (0.96, 1.22) | 0.08 |
| Non-egg cholesterol6 | 1.00 | 0.99 (0.90, 1.08) | 1.01 (0.92, 1.10) | 1.05 (0.95, 1.15) | 1.15 (1.05, 1.27) | <0.0001 |
| Non-egg choline6 | 1.00 | 1.00 (0.91, 1.09) | 1.02 (0.93, 1.12) | 1.08 (0.99, 1.18) | 1.22 (1.12, 1.33) | <0.0001 |
| Non-egg cholesterol and non-egg choline | 1.00 | 0.99 (0.90, 1.08) | 1.00 (0.91, 1.10) | 1.04 (0.95, 1.15) | 1.15 (1.05, 1.27) | 0.0001 |
| Exposure: total cholesterol consumption | ||||||
| Cases/women | 841/8578 | 1029/9879 | 1118/9885 | 1215/9437 | 1273/8449 | |
| Total choline | 1.00 | 1.04 (0.94, 1.15) | 1.08 (0.97, 1.21) | 1.23 (1.09, 1.39) | 1.29 (1.13, 1.48) | <0.0001 |
| Total choline and total betaine | 1.00 | 1.03 (0.94, 1.14) | 1.07 (0.96, 1.20) | 1.21 (1.08, 1.37) | 1.26 (1.10, 1.45) | 0.0002 |
| Exposure: total choline consumption | ||||||
| Cases/women | 795/7,495 | 1068/9799 | 1176/10,038 | 1145/9812 | 1292/9084 | |
| Total cholesterol | 1.00 | 0.99 (0.89, 1.09) | 1.00 (0.89, 1.13) | 0.96 (0.84, 1.09) | 1.06 (0.90, 1.24) | 0.39 |
| Total cholesterol and total betaine | 1.00 | 1.00 (0.90, 1.11) | 1.02 (0.90, 1.15) | 0.98 (0.85, 1.12) | 1.10 (0.93, 1.29) | 0.19 |
| Exposure: total betaine consumption | ||||||
| Cases/women | 885/7705 | 1097/9330 | 1179/9656 | 1192/9790 | 1123/9747 | |
| Total cholesterol | 1.00 | 0.99 (0.90, 1.08) | 1.01 (0.92, 1.10) | 0.99 (0.90, 1.09) | 0.91 (0.82, 1.01) | 0.08 |
| Total cholesterol and total choline | 1.00 | 0.99 (0.90, 1.09) | 1.01 (0.92, 1.11) | 0.99 (0.90, 1.09) | 0.90 (0.81, 1.003) | 0.03 |
HRs and 95% CIs were determined by means of Cox regression. The 4 baseline nutrient exposure variables were each the mean of the year 0 and year 3 values at year 3 (follow-up baseline), when the WHI FFQ was readministered. Incident diabetes was the first occurrence of self-reported diabetes treated with pills or injections between the year 3 baseline survey and March 31, 2018. All models were full models that were adjusted for age (years), self-reported race/ethnicity (white, black, other), and several continuous and categorical variables. The full model included additional continuous and categorical variables. The continuous variables were BMI, 3-y BMI change, the Revised Alternative Healthy Eating Index (27), non-egg daily energy intake for models with eggs as the exposure variable, and total daily energy intake for models with an egg nutrient as the exposure variable. Energy intake was derived from FFQ data, physical activity (total energy expended from recreational physical activity in MET-h/wk), smoking status (never, past, current), alcohol intake in drinks/wk (0, 0 to <1, 1 to <6, >6), educational level (less than high school grad, high school grad to some college, college grad to less than master's degree, master's degree or higher), and coffee consumption (0–6 cups/d). Our analytic sample included observational study participants without 1) implausible FFQ energy intakes (defined as mean intakes <600 or >5000 kcal/d), BMI (<15 or >50), or height <122 cm (4 ft); 2) any of the following pre-existing major chronic conditions at follow-up baseline: diabetes, angina, myocardial infarction, stroke, heart failure, emphysema, kidney dialysis, coronary artery bypass graft, percutaneous coronary intervention, or cancer; or 3) missing values on any pre-existing major chronic condition or any exposure, outcome, or confounder variables. MET, metabolic equivalent; WHI, Women's Health Initiative.
Quintile categories at baseline (year 3) were as follows: egg consumption: <1.6/mo, 1.6 to <4/mo, 4 to <6.6/mo, 6.6/mo to <3/wk, and ≥3/wk; cholesterol (mg/day): <115.6, 115.6 to <159.3, 159.3 to <206.0, 206.0 to <276.0, and ≥276.0; choline (mg/day): <184.0, 184.0 to < 233.1, 233.1 to <280.7, 280.7 to <343.7, and ≥343.7; betaine (mg/day): <103.5, 103.5 to <140.6, 140.6 to <179.3, 179.3 to <234.1, and ≥234.1. Egg, cholesterol, choline, and betaine consumption were assessed by means of a semiquantitative FFQ.
Referent category.
Tests for linear trend were performed by using the median in each exposure quintile as the sole exposure variable in the model.
Cases, the number of incident diabetes events during the 13.3-y follow-up period. Women, the number of participants without pre-existing serious chronic disease at year 3 (baseline) who met all our inclusion criteria.
Non-egg cholesterol consumption was total cholesterol consumption minus the number of medium-sized eggs consumed multiplied by the cholesterol content of such eggs (164 mg/egg). Non-egg choline consumption was total choline consumption minus the number of medium-sized eggs consumed multiplied by the choline content of such eggs (129 mg/egg). Both the cholesterol content and the choline content of medium-sized eggs were obtained from the US Department of Agriculture, Agricultural Research Service (33).