Table 3. Relative risk (95% CI) of total and cardiovascular mortality according to frequency of bowel movements in the Nurses’ Health Study (1982–2012).
| Frequency of bowel movements |
P for trend* | |||||
|---|---|---|---|---|---|---|
| > 1/Day | Daily | Every 2 days | Every 3–4 days | Every 5 days or less | ||
| Total mortality | ||||||
| Cases/person-years | 2806/241676 | 13694/1495739 | 3078/439869 | 1264/177837 | 242/29735 | |
| Model 1† | 1.25 (1.20, 1.30) | 1.00 (reference) | 0.88 (0.85, 0.91) | 0.90 (0.85, 0.95) | 0.99 (0.87, 1.12) | < 0.001 |
| Model 2‡ | 1.18 (1.14, 1.23) | 1.00 (reference) | 0.92 (0.88, 0.96) | 0.92 (0.87, 0.97) | 1.01 (0.89, 1.15) | < 0.001 |
| Model 3§ | 1.17 (1.12, 1.22) | 1.00 (reference) | 0.92 (0.89, 0.96) | 0.92 (0.87, 0.97) | 1.01 (0.89, 1.15) | < 0.001 |
| Model 4|| | 1.10 (1.06, 1.15) | 1.00 (reference) | 0.94 (0.90, 0.97) | 0.94 (0.89, 0.99) | 1.04 (0.91, 1.18) | < 0.001 |
| Cardiovascular mortality | ||||||
| Cases/person-years | 644/243635 | 2955/1505636 | 604/442114 | 244/178752 | 44/29933 | |
| Model 1† | 1.32 (1.21, 1.44) | 1.00 (reference) | 0.83 (0.76, 0.91) | 0.84 (0.74, 0.96) | 0.86 (0.64, 1.15) | < 0.001 |
| Model 2‡ | 1.19 (1.09, 1.30) | 1.00 (reference) | 0.88 (0.80, 0.96) | 0.87 (0.76, 0.99) | 0.89 (0.66, 1.20) | < 0.001 |
| Model 3§ | 1.17 (1.07, 1.28) | 1.00 (reference) | 0.87 (0.80, 0.95) | 0.86 (0.75, 0.98) | 0.88 (0.65, 1.19) | < 0.001 |
| Model 4|| | 1.05 (0.96, 1.15) | 1.00 (reference) | 0.90 (0.82, 0.98) | 0.90 (0.79, 1.02) | 0.92 (0.68, 1.24) | 0.005 |
*P for trend was assessed by assigning the mid-point value in each category to participants and evaluating this as a continuous variable. Model adjustments were the same as shown in Table 2.