Table 3.
Association Between Bowel Movement Frequency and 3-Unit Increments in Subjective Cognitive Decline in the Nurses' Health Study (NHS), the Nurses' Health Study II (NHSII), and the Health Professionals Follow-Up Study (HPFS)a
| Frequency of bowel movement | p nonlinearity b | ||||
| Every 3+ d | Every 2 d | Daily | ≥Twice/day | ||
| NHS | |||||
| Model 1 | 2.70 (2.42–3.01) | 1.62 (1.49–1.76) | 1 (ref.) | 1.41 (1.31–1.51) | <0.001 |
| Model 2 | 1.99 (1.78–2.22) | 1.37 (1.26–1.48) | 1 (ref.) | 1.38 (1.28–1.49) | <0.001 |
| Model 3 | 1.90 (1.61–2.01) | 1.30 (1.20–1.41) | 1 (ref.) | 1.41 (1.31–1.51) | <0.001 |
| NHSII | |||||
| Model 1 | 2.64 (2.39–2.92) | 1.54 (1.43–1.65) | 1 (ref.) | 1.53 (1.43–1.64) | <0.001 |
| Model 2 | 1.84 (1.66–2.03) | 1.32 (1.22–1.42) | 1 (ref.) | 1.40 (1.31–1.50) | <0.001 |
| Model 3 | 1.64 (1.48–1.82) | 1.27 (1.18–1.37) | 1 (ref.) | 1.36 (1.27–1.46) | <0.001 |
| HPFS | |||||
| Model 1 | 2.49 (1.78–3.49) | 1.37 (1.11–1.70) | 1 (ref.) | 1.25 (1.10–1.42) | <0.001 |
| Model 2 | 1.94 (1.38–2.72) | 1.18 (0.96–1.47) | 1 (ref.) | 1.27 (1.12–1.45) | <0.001 |
| Model 3 | 1.61 (1.13–2.28) | 1.06 (0.85–1.32) | 1 (ref.) | 1.32 (1.16–1.51) | <0.001 |
| Pooledc | |||||
| Model 1 | 2.69 (2.46–2.86) | 1.56 (1.48–1.64) | 1 (ref.) | 1.44 (1.37–1.52) | <0.001 |
| Model 2 | 1.91 (1.77–2.05) | 1.33 (1.26–1.40) | 1 (ref.) | 1.37 (1.33–1.44) | <0.001 |
| Model 3 | 1.73 (1.60–1.86) | 1.26 (1.19–1.33) | 1 (ref.) | 1.37 (1.33–1.44) | <0.001 |
Model 1 adjusted for age at cognitive function assessment and educational attainment of parents and spouse.
Model 2 further adjusted for antibiotic use, laxative use, antidepressant use, and symptoms of depression.
Model 3 further adjusted for neighborhood socioeconomic status index, Alternative Healthy Eating Index, fiber intake, smoking status, physical activity level, marriage status, living arrangement, and histories of hypertension, diabetes, hypercholesterolemia, hyperthyroidism, and hypothyroidism.
Values are multivariable-adjusted odds ratios (95% CI) of 3-unit increments in subjective cognitive decline comparing participants with higher or lower frequencies of bowel movement to those with daily bowel movement estimated from Poisson regression models.
We modeled nonlinear associations between bowel movement frequency and cognitive function scores using restricted cubic splines; potential nonlinearity was tested by using a likelihood ratio test.
Results for NHS, NHSII, and HPFS from the multivariable model were combined using the fixed effects model.