Fermented Dairy Food Intake and Risk of Depression and Dementia in Later Life: Findings from a Prospective Cohort of Older Australians
Abstract
1. Introduction
2. Methods
3. Ethics Approval
4. Habitual Dietary Intake
5. Exposure of Interest
6. Outcomes
6.1. Depressive Symptoms and Psychological Distress
6.2. Incidence of Depression
6.3. Cognitive Decline Outcomes
6.4. Incidence of Dementia
7. Other Covariates
8. Statistical Analysis
8.1. Cross-Sectional Analysis
8.2. Longitudinal Analysis
8.3. Analysis of Non-Fermented Dairy Foods
9. Results
9.1. Cross-Sectional Analysis
9.2. Longitudinal Analysis
10. Discussion
11. Conclusions
Supplementary Materials
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
References
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| Total | Quartile 1 (Lowest Quartile, No Intake) | Quartile 2 | Quartile 3 | Quartile 4 (Highest Quartile) | |
|---|---|---|---|---|---|
| N | 966 (100.0%) | 303 (31.4%) | 293 (30.3%) | 188 (19.5%) | 182 (18.8%) |
| Yogurt intake (g/day), mean (SD) | 53.7 (67.8) | 0 | 18.1 (15.0) | 88.5 (20.0) | 164.2 (57.4) |
| Age (years) | 78.39 (4.8) | 78.9 (5.0) | 77.9 (4.8) | 77.6 (4.4) | 78.5 (4.9) |
| Sex | |||||
| Men | 430 (44.5%) | 173 (57.1%) | 121 (41.3%) | 63 (33.5%) | 73 (40.1%) |
| Women | 536 (55.5%) | 130 (42.9%) | 172 (58.7%) | 125 (66.5%) | 109 (59.9%) |
| Education level | |||||
| High school or below | 679 (70.3%) | 215 (71.0%) | 203 (69.3%) | 135 (71.8%) | 126 (69.2%) |
| Vocational education and training | 87 (9.0%) | 25 (8.3%) | 28 (9.6%) | 17 (9.0%) | 17 (9.3%) |
| University or above | 200 (20.7%) | 63 (20.8%) | 62 (21.2%) | 36 (19.1%) | 39 (21.4%) |
| English-speaking background | |||||
| English | 816 (84.5%) | 265 (87.5%) | 242 (82.6%) | 156 (83.0%) | 153 (84.1%) |
| Non-English | 150 (15.5%) | 38 (12.5%) | 51 (17.4%) | 32 (17.0%) | 29 (15.9%) |
| Main occupation before retirement | |||||
| Manager/professional | 481 (49.8%) | 139 (45.9%) | 154 (52.6%) | 90 (47.9%) | 98 (53.8%) |
| Clerical/service | 335 (34.7%) | 121 (39.9%) | 85 (29.0%) | 70 (37.2%) | 59 (32.4%) |
| Trade/labor | 94 (9.7%) | 22 (7.3%) | 41 (14.0%) | 17 (9.0%) | 14 (7.7%) |
| Homemakers or other | 56 (5.8%) | 21 (6.9%) | 13 (4.4%) | 11 (5.9%) | 11 (6.0%) |
| BMI (kg/m2) | 27.2 (4.5) | 27.4 (4.5) | 27.4 (4.7) | 26.6 (4.1) | 26.9 (4.6) |
| Smoking status | |||||
| Never smokers | 447 (46.3%) | 143 (47.2%) | 139 (47.4%) | 88 (46.8%) | 77 (42.3%) |
| Former smokers | 485 (50.3%) | 147 (48.5%) | 144 (49.1%) | 97 (51.6%) | 97 (53.6%) |
| Current smokers | 34 (3.5%) | 10 (3.3%) | 15 (5.1%) | 4 (2.1%) | 5 (2.8%) |
| Alcohol consumption | |||||
| Never drinkers | 52 (5.4%) | 18 (5.9%) | 16 (5.5%) | 10 (5.3%) | 8 (4.4%) |
| Former drinkers | 68 (7.0%) | 17 (5.6%) | 22 (7.5%) | 14 (7.4%) | 15 (8.2%) |
| Current drinkers | 841 (87.1%) | 264 (87.1%) | 257 (87.7%) | 163 (86.7%) | 157 (86.3%) |
| Moderate or vigorous physical activity (minutes/week) | 74.4 (162.7) | 47.8 (122.7) | 84.8(175.3) | 84.6 (189.2) | 91.4 (166.4) |
| Social engagement (in-person contact, times/month) | 2.2 (0.8) | 2.25 (0.89) | 2.22 (0.7) | 2.20 (0.7) | 2.20 (0.8) |
| Total energy intake (kilojoules/day) | 6426.2 (2081.2) | 6267.4 (2062.4) | 6440.4 (2141.5) | 6290.1 (2010.2) | 6813.3 (2051.5) |
| Dietary index score | 43.8 (10.1) | 40.6 (10.2) | 43.9 (9.9) | 46.4 (9.3) | 46.1 (9.7) |
| Antidepressant use at baseline | |||||
| No | 842 (87.2%) | 265 (87.5%) | 255 (87.0%) | 160 (85.1%) | 162 (89.0%) |
| Yes | 124 (12.8%) | 38 (12.5%) | 38 (13.0%) | 28 (14.9%) | 20 (11.0%) |
| APOE ε4 carrier | |||||
| Non-carrier | 717 (77.1%) | 229 (77.9%) | 222 (78.7%) | 133 (75.1%) | 133 (75.1%) |
| Carrier | 213 (22.9%) | 65 (22.1%) | 60 (21.3%) | 44 (24.9%) | 44 (24.9%) |
| Diabetes prevalence | |||||
| No | 586 (60.7%) | 178 (58.7%) | 178 (60.8%) | 118 (62.8%) | 112 (61.5%) |
| Yes | 380 (39.3%) | 125 (41.3%) | 115 (39.2%) | 70 (37.2%) | 70 (38.5%) |
| Hypertension prevalence | |||||
| No | 135 (14.0%) | 39 (12.9%) | 39 (13.3%) | 26 (13.8%) | 31 (17.0%) |
| Yes | 831 (86.0%) | 264 (87.1%) | 254 (86.7%) | 162 (86.2%) | 151 (83.0%) |
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Idrus, M.; Bliuc, D.; Mather, K.A.; Brodaty, H.; Sachdev, P.S.; Numbers, K.; Dai, Z. Fermented Dairy Food Intake and Risk of Depression and Dementia in Later Life: Findings from a Prospective Cohort of Older Australians. Nutrients 2026, 18, 1020. https://doi.org/10.3390/nu18071020
Idrus M, Bliuc D, Mather KA, Brodaty H, Sachdev PS, Numbers K, Dai Z. Fermented Dairy Food Intake and Risk of Depression and Dementia in Later Life: Findings from a Prospective Cohort of Older Australians. Nutrients. 2026; 18(7):1020. https://doi.org/10.3390/nu18071020
Chicago/Turabian StyleIdrus, Muniratul, Dana Bliuc, Karen A. Mather, Henry Brodaty, Perminder S. Sachdev, Katya Numbers, and Zhaoli Dai. 2026. "Fermented Dairy Food Intake and Risk of Depression and Dementia in Later Life: Findings from a Prospective Cohort of Older Australians" Nutrients 18, no. 7: 1020. https://doi.org/10.3390/nu18071020
APA StyleIdrus, M., Bliuc, D., Mather, K. A., Brodaty, H., Sachdev, P. S., Numbers, K., & Dai, Z. (2026). Fermented Dairy Food Intake and Risk of Depression and Dementia in Later Life: Findings from a Prospective Cohort of Older Australians. Nutrients, 18(7), 1020. https://doi.org/10.3390/nu18071020

