Table 3. Multivariable-Adjusted Differences in Standardized Cognitive Scores Associated With Quintiles of Gluten Intake, According to Different Strataa.
| Strata | No. | Difference by quintiles of gluten intake, mean (95% CI) | P value | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 1, lowest | 2 | 3 | 4 | 5 (highest) | For trendb | For interactionc | ||||
| Psychomotor speed and attentiond | ||||||||||
| Age, y | ||||||||||
| <65 | 10 234 | 0 [Reference] | 0.02 (−0.04 to 0.08) | 0.03 (−0.03 to 0.09) | −0.03 (−0.09 to 0.03) | −0.02 (−0.08 to 0.04) | .15 | .62 | ||
| ≥65 | 3260 | 0 [Reference] | −0.02 (−0.13 to 0.09) | −0.05 (−0.16 to 0.06) | −0.01 (−0.12 to 0.11) | 0.004 (−0.11 to 0.12) | .90 | |||
| Smoking | ||||||||||
| Never | 8932 | 0 [Reference] | 0.02 (−0.05 to 0.08) | 0.02 (−0.05 to 0.08) | 0.01 (−0.06 to 0.07) | 0.01 (−0.05 to 0.08) | .88 | .02 | ||
| Ever | 4550 | 0 [Reference] | 0.003 (−0.09 to 0.09) | 0.01 (−0.08 to 0.09) | −0.09 (−0.18 to 0.002) | −0.09 (−0.18 to 0.01) | .02 | |||
| BMI | ||||||||||
| <25 | 7032 | 0 [Reference] | 0.01 (−0.07 to 0.08) | 0.002 (−0.07 to 0.08) | −0.06 (−0.14 to 0.01) | −0.05 (−0.12 to 0.02) | .05 | .31 | ||
| ≥25 | 6462 | 0 [Reference] | 0.01 (−0.06 to 0.09) | 0.02 (−0.05 to 0.10) | 0.02 (−0.06 to 0.09) | 0.005 (−0.07 to 0.08) | .91 | |||
| Current depression status | ||||||||||
| No | 9217 | 0 [Reference] | 0.001 (−0.06 to 0.06) | −0.004 (−0.07 to 0.06) | −0.01 (−0.07 to 0.05) | −0.02 (−0.09 to 0.04) | .43 | .62 | ||
| Yes | 4277 | 0 [Reference] | 0.03 (−0.07 to 0.13) | 0.05 (−0.05 to 0.15) | −0.05 (−0.15 to 0.05) | −0.05 (−0.15 to 0.05) | .33 | |||
| History of diabetes | ||||||||||
| No | 12 503 | 0 [Reference] | 0.02 (−0.04 to 0.07) | 0.02 (−0.04 to 0.07) | −0.02 (−0.07 to 0.04) | −0.01 (−0.07 to 0.04) | .34 | .41 | ||
| Yes | 991 | 0 [Reference] | −0.11 (−0.31 to 0.08) | −0.06 (−0.26 to 0.14) | −0.11 (−0.33 to 0.10) | −0.15 (−0.38 to 0.07) | .21 | |||
| History of hypertension | ||||||||||
| No | 8337 | 0 [Reference] | 0.01 (−0.06 to 0.08) | 0.01 (−0.06 to 0.08) | −0.05 (−0.12 to 0.02) | −0.04 (−0.11 to 0.03) | .07 | .17 | ||
| Yes | 5157 | 0 [Reference] | 0.02 (−0.07 to 0.10) | 0.02 (−0.07 to 0.10) | 0.02 (−0.07 to 0.11) | 0.01 (−0.08 to 0.10) | .75 | |||
| History of hypercholesterolemia | ||||||||||
| No | 5616 | 0 [Reference] | −0.01 (−0.09 to 0.08) | −0.04 (−0.12 to 0.05) | −0.08 (−0.16 to −0.001) | −0.07 (−0.15 to 0.01) | .03 | .10 | ||
| Yes | 7878 | 0 [Reference] | 0.02 (−0.05 to 0.09) | 0.04 (−0.02 to 0.11) | 0.01 (−0.06 to 0.08) | 0.01 (−0.07 to 0.08) | .99 | |||
| Learning and working memoryd | ||||||||||
| Age, y | ||||||||||
| <65 | 10 234 | 0 [Reference] | 0.02 (−0.03 to 0.08) | 0.11 (0.05 to 0.16) | 0.07 (0.01 to 0.13) | 0.04 (−0.02 to 0.10) | .16 | .19 | ||
| ≥65 | 3260 | 0 [Reference] | −0.01 (−0.12 to 0.09) | −0.01 (−0.11 to 0.10) | −0.04 (−0.14 to 0.07) | −0.004 (−0.11 to 0.10) | .80 | |||
| Smoking | ||||||||||
| Never | 8932 | 0 [Reference] | 0.01 (−0.05 to 0.08) | 0.06 (−0.01 to 0.12) | 0.06 (−0.001 to 0.13) | 0.03 (−0.04 to 0.09) | .24 | .31 | ||
| Ever | 4550 | 0 [Reference] | 0.02 (−0.07 to 0.10) | 0.10 (0.02 to 0.19) | −0.01 (−0.09 to 0.08) | 0.01 (−0.08 to 0.10) | .99 | |||
| BMI | ||||||||||
| <25 | 7032 | 0 [Reference] | −0.02 (−0.09 to 0.06) | 0.06 (−0.02 to 0.13) | 0.05 (−0.02 to 0.12) | −0.001 (−0.07 to 0.07) | .62 | .78 | ||
| ≥25 | 6462 | 0 [Reference] | 0.04 (−0.03 to 0.12) | 0.10 (0.02 to 0.17) | 0.02 (−0.05 to 0.10) | 0.05 (−0.03 to 0.13) | .33 | |||
| Current depression status | ||||||||||
| No | 9217 | 0 [Reference] | −0.01 (−0.07 to 0.05) | 0.06 (0.003 to 0.12) | 0.06 (0.0002 to 0.12) | 0.03 (−0.03 to 0.09) | .10 | .13 | ||
| Yes | 4277 | 0 [Reference] | 0.06 (−0.04 to 0.15) | 0.09 (−0.001 to 0.19) | 0.005 (−0.09 to 0.10) | 0.01 (−0.09 to 0.10) | .65 | |||
| History of diabetes | ||||||||||
| No | 12 503 | 0 [Reference] | 0.02 (−0.03 to 0.07) | 0.08 (0.03 to 0.14) | 0.05 (−0.003 to 0.10) | 0.03 (−0.03 to 0.08) | .26 | .63 | ||
| Yes | 991 | 0 [Reference] | −0.07 (−0.26 to 0.12) | −0.03 (−0.22 to 0.16) | −0.06 (−0.27 to 0.15) | −0.01 (−0.22 to 0.21) | .95 | |||
| History of hypertension | ||||||||||
| No | 8337 | 0 [Reference] | 0.001 (−0.07 to 0.07) | 0.07 (0.002 to 0.13) | 0.04 (−0.03 to 0.10) | 0.02 (−0.04 to 0.09) | .36 | .94 | ||
| Yes | 5157 | 0 [Reference] | 0.03 (−0.05 to 0.11) | 0.08 (0.001 to 0.16) | 0.05 (−0.04 to 0.13) | 0.02 (−0.07 to 0.11) | .57 | |||
| History of hypercholesterolemia | ||||||||||
| No | 5616 | 0 [Reference] | −0.08 (−0.16 to 0.005) | −0.03 (−0.11 to 0.05) | −0.03 (−0.11 to 0.05) | −0.06 (−0.14 to 0.02) | .45 | .07 | ||
| Yes | 7878 | 0 [Reference] | 0.07 (0.01 to 0.14) | 0.14 (0.08 to 0.21) | 0.08 (0.02 to 0.15) | 0.07 (0.004 to 0.14) | .04 | |||
| Global cognitiond | ||||||||||
| Age, y | ||||||||||
| <65 | 10 234 | 0 [Reference] | 0.03 (−0.03 to 0.09) | 0.08 (0.02 to 0.14) | 0.02 (−0.04 to 0.08) | 0.004 (−.06 to 0.06) | .84 | .72 | ||
| ≥65 | 3260 | 0 [Reference] | −0.02 (−0.13 to 0.08) | −0.04 (−0.14 to 0.07) | −0.03 (−0.14 to 0.08) | 0.0001 (−0.11 to 0.11) | .96 | |||
| Smoking | ||||||||||
| Never | 8932 | 0 [Reference] | 0.02 (−0.05 to 0.08) | 0.04 (−0.02 to 0.11) | 0.04 (−0.03 to 0.10) | 0.02 (−0.04 to 0.09) | .46 | .03 | ||
| Ever | 4550 | 0 [Reference] | 0.01 (−0.07 to 0.10) | 0.06 (−0.03 to 0.15) | −0.06 (−0.15 to 0.03) | −0.05 (−0.15 to 0.04) | .10 | |||
| BMI | ||||||||||
| <25 | 7032 | 0 [Reference] | −0.003 (−0.08 to 0.07) | 0.03 (−0.04 to 0.10) | −0.01 (−0.09 to 0.06) | −0.03 (−0.10 to 0.04) | .29 | .41 | ||
| ≥25 | 6462 | 0 [Reference] | 0.03 (−0.04 to 0.11) | 0.07 (−0.01 to 0.14) | 0.02 (−0.05 to 0.10) | 0.03 (−0.05 to 0.11) | .55 | |||
| Current depression status | ||||||||||
| No | 9217 | 0 [Reference] | −0.005 (−0.06 to 0.06) | 0.03 (−0.03 to 0.09) | 0.03 (−0.04 to 0.09) | 0.002 (−0.06 to 0.06) | .73 | .25 | ||
| Yes | 4277 | 0 [Reference] | 0.05 (−0.05 to 0.15) | 0.08 (−0.01 to 0.18) | −0.03 (−0.13 to 0.07) | −0.01 (−0.11 to 0.09) | .37 | |||
| History of diabetes | ||||||||||
| No | 12 503 | 0 [Reference] | 0.02 (−0.03 to 0.08) | 0.06 (0.004 to 0.11) | 0.01 (−0.04 to 0.07) | 0.01 (−0.05 to 0.06) | .96 | .41 | ||
| Yes | 991 | 0 [Reference] | −0.11 (−0.31 to 0.08) | −0.06 (−0.25 to 0.13) | −0.11 (−0.32 to 0.10) | −0.11 (−0.32 to 0.11) | .37 | |||
| History of hypertension | ||||||||||
| No | 8337 | 0 [Reference] | 0.01 (−0.06 to 0.07) | 0.04 (−0.02 to 0.11) | −0.01 (−0.08 to 0.05) | −0.01 (−0.08 to 0.05) | .47 | .34 | ||
| Yes | 5157 | 0 [Reference] | 0.03 (−0.05 to 0.11) | 0.06 (−0.03 to 0.14) | 0.04 (−0.05 to 0.13) | 0.02 (−0.07 to 0.11) | .61 | |||
| History of hypercholesterolemia | ||||||||||
| No | 5616 | 0 [Reference] | −0.05 (−0.13 to 0.04) | −0.04 (−0.12 to 0.04) | −0.07 (−0.15 to 0.01) | −0.07 (−0.15 to 0.01) | .06 | .04 | ||
| Yes | 7878 | 0 [Reference] | 0.05 (−0.01 to 0.12) | 0.11 (0.04 to 0.17) | 0.05 (−0.02 to 0.12) | 0.04 (−0.03 to 0.11) | .28 | |||
Abbreviation: BMI, body mass index (calculated as weight in kilograms divided by height in meters squared).
a
Energy-adjusted gluten intake was cumulatively averaged from 1991 to the last questionnaire cycle preceding the cognitive assessment. Model was adjusted for age, race, body mass index, husband’s educational attainment, family income, history of diabetes, history of hypertension, history of hypercholesterolemia, history of myocardial infarction, current depression status, smoking, aspirin or nonsteroid anti-inflammatory drug use, multivitamins use, physical activity, menopausal status and hormone use, total energy intake, alcohol intake, and Alternative Healthy Eating Index score, excluding alcohol and whole grains.
b
P value for trend was calculated using the median value for each gluten intake quintile as a continuous variable.
c
P value for interaction was estimated using an interaction term of gluten intake and the respective stratifying variable.
d
Standardized scores for psychomotor speed and attention, learning and working memory, and global cognition were calculated by standardizing the mean standardized scores of the following Cogstate battery tasks: Detection and Identification, One Card Learning and One Back, and all 4 four tasks, respectively. Higher scores indicate better performance, with 1 unit increase representing 1 SD higher than the mean.