Table 3.
Multivariable-adjusted odds ratios of lifetime depression a, by trimester, among participants in Nurses’ Health Study and Nurses’ Health Study II combined across quintiles of total photoperiod and extreme differences in photoperiod during maternal pregnancy (n=160,737)
| QUINTILES OF TOTAL PHOTOPERIOD DURING MATERNAL PREGNANCY | ||||||
|---|---|---|---|---|---|---|
| First trimester | ||||||
| Quintile 1 (909 hours) | Quintile 2 (995 hours) | Quintile 3 (1,127 hours) | Quintile 4 (1,264 hours) | Quintile 5 (1,357 hours) | p-trend | |
| Cases of depression (%) | 5,461 (16.99%) | 5,679 (17.67%) | 5,731 (17.83%) | 5,755 (17.90%) | 5,554 (17.28%) | |
| Multivariable-adjusted OR, 95% CI b | 1.00 (ref) | 1.05 (1.01, 1.09) | 1.06 (1.02, 1.11) | 1.07 (1.02, 1.11) | 1.02 (0.98, 1.07) | 0.18 |
| Second trimester | ||||||
| Quintile 1 (911 hours) | Quintile 2 (1,007 hours) | Quintile 3 (1,140 hours) | Quintile 4 (1,269 hours) | Quintile 5 (1,357 hours) | ||
| Cases of depression (%) | 5,601 (17.42%) | 5,667 (17.63%) | 5,681 (17.67%) | 5,709 (17.76%) | 5,522 (17.18%) | |
| Multivariable-adjusted OR, 95% CI b | 1.00 (ref) | 1.09 (1.04, 1.15) | 1.14 (1.08, 1.20) | 1.09 (1.04, 1.14) | 0.98 (0.94, 1.02) | 0.51 |
| Third trimester | ||||||
| Quintile 1 (921 hours) | Quintile 2 (1,018 hours) | Quintile 3 (1,158 hours) | Quintile 4 (1,288 hours) | Quintile 5 (1,372 hours) | ||
| Cases of depression (%) | 5,540 (17.23%) | 5,756 (17.91%) | 5,717 (17.78%) | 5,694 (17.71%) | 5,473 (17.02%) | |
| Multivariable-adjusted OR, 95% CI b | 1.00 (ref) | 1.12 (1.01, 1.23) | 1.17 (1.02, 1.34) | 1.21 (1.03, 1.43) | 1.19 (0.99, 1.44) | 0.09 |
| QUINTILES OF EXTREME DIFFERENCES IN PHOTOPERIOD DURING MATERNAL PREGNANCY | ||||||
| First trimester | ||||||
| Quintile 1 (1.30 hours) | Quintile 2 (2.05 hours) | Quintile 3 (2.78 hours) | Quintile 4 (3.48 hours) | Quintile 5 (3.92 hours) | p-trend | |
| Cases of depression (%) | 5,729 (17.82%) | 5,731 (17.83%) | 5,646 (17.56%) | 5,609 (17.45%) | 5,465 (17.00%) | |
| Multivariable-adjusted OR, 95% CI c | 1.00 (ref) | 1.00 (0.96, 1.04) | 0.98 (0.94, 1.02) | 0.98 (0.94, 1.02) | 0.96 (0.92, 1.00) | 0.02 |
| Second trimester | ||||||
| Quintile 1 (1.30 hours) | Quintile 2 (2.08 hours) | Quintile 3 (2.82 hours) | Quintile 4 (3.50 hours) | Quintile 5 (3.92 hours) | ||
| Cases of depression (%) | 5,687 (17.69%) | 5,796 (18.03%) | 5,727 (17.82%) | 5,614 (17.46%) | 5,356 (16.66%) | |
| Multivariable-adjusted OR, 95% CI c | 1.00 (ref) | 1.00 (0.95, 1.04) | 0.92 (0.87, 0.97) | 0.84 (0.80, 0.89) | 0.77 (0.72, 0.82) | <0.001 |
| Third trimester | ||||||
| Quintile 1 (1.32 hours) | Quintile 2 (2.07 hours) | Quintile 3 (2.80 hours) | Quintile 4 (3.52 hours) | Quintile 5 (3.95 hours) | ||
| Cases of depression (%) | 5,731 (17.83%) | 5,684 (17.68%) | 5,665 (17.62%) | 5,637 (17.54%) | 5,463 (16.99%) | |
| Multivariable-adjusted OR, 95% CI c | 1.00 (ref) | 0.97 (0.91, 1.03) | 0.96 (0.88, 1.05) | 0.96 (0.85, 1.07) | 0.93 (0.81, 1.06) | 0.45 |
Abbreviations: CI=confidence interval; OR=odds ratio
Defined as cases with clinician-diagnosed depression and antidepressant medication use during follow up.
Models are adjusted for birth year (⩽1925, 1926–1930, 1931–1935, 1936–1940, ⩾1941 in NHS, and ⩽1945, 1946–1950, 1951–1955, ⩾1956 in NHS II), race (white, black, other), hair color (dark brown, light brown, black, blond, red, missing), parent’s home ownership at birth (yes, no, missing), mother’s occupation in childhood (professional/executive, sales/clerical, craftsman/service, laborer/farmer/military, stay at home parent, missing), father’s occupation in childhood (professional/executive, sales/clerical, craftsman/service, laborer/farmer/military, stay at home parent, missing), mother’s smoking status during pregnancy (yes, no, missing), birth weight (<5.5, 5.5–6.9, 7–8.4, 8.5+ pounds, missing), breastfeeding (yes, no, missing), and total perinatal photoperiod during previous trimesters (in quintiles).
Models are adjusted for birth year (⩽1925, 1926–1930, 1931–1935, 1936–1940, ⩾1941 in NHS, and ⩽1945, 1946–1950, 1951–1955, ⩾1956 in NHS II), race (white, black, other), hair color (dark brown, light brown, black, blond, red, missing), parent’s home ownership at birth (yes, no, missing), mother’s occupation in childhood (professional/executive, sales/clerical, craftsman/service, laborer/farmer/military, stay at home parent, missing), father’s occupation in childhood (professional/executive, sales/clerical, craftsman/service, laborer/farmer/military, stay at home parent, missing), mother’s smoking status during pregnancy (yes, no, missing), birth weight (<5.5, 5.5–6.9, 7–8.4, 8.5+ pounds, missing), breastfeeding (yes, no, missing), and extreme differences in perinatal photoperiod during previous trimesters (in quintiles).