Introduction
Materials and methods
Study design and participants
Diet quality assessment
Food groups | Guideline | |
---|---|---|
1 | Vegetables | ≥ 200 g/day |
2 | Fruit | ≥ 200 g/day |
3 | Whole grain products | ≥ 90 g/day |
4 | Legumes | ≥ 135 g/week |
5 | Nuts | ≥ 15 g/day |
6 | Dairy | ≥ 350 g/day |
7 | Fish | ≥ 100 g/week |
8 | Tea | ≥ 450 ml/day |
9 | Unsaturated fat and oil ratio | Replace fats ≥ 50% of total fats as healthy fatsa |
10 | Whole grain ratio | Replace refined grains ≥ 50% of total grains as whole grains |
11 | Red and processed meat | < 300 g/week |
12 | Sugar-containing beverages | < 150 ml/day |
13 | Alcohol | ≤ 10 g/day |
14 | Salt | ≤ 6 g/day |
Covariate assessment
Statistical analyses
Results
Characteristics of the study population
Characteristics | Overall |
N
| Winter |
N
| Spring |
N
| Summer |
N
| Autumn |
N
| P value* |
---|---|---|---|---|---|---|---|---|---|---|---|
Median (IQR) | Median (IQR) | Median (IQR) | Median (IQR) | Median (IQR) | |||||||
Age (years) | 66.3 (59.4–73.7) | 12,589 | 66.3 (59.8–73.5) | 3239 | 66.5 (58.8 to 74.1) | 3951 | 67.3 (59.7–74.5) | 2868 | 64.7 (59.3–72.5) | 2531 | < 0.01 |
Physical activity (z score MET-hours/week)a | − 0.22 (− 0.77 to 0.58) | 10,412 | − 0.19 (− 0.75 to 0.55) | 2643 | − 0.26 (− 0.78 to 0.48) | 3301 | − 0.23 (− 0.78 to 0.56) | 2388 | − 0.11 (− 0.77 to 0.78) | 2080 | < 0.01 |
BMI | 26.5 (24.3–29.1) | 12,397 | 26.3 (24.2–29.0) | 3204 | 26.6 (24.3–29.3) | 3882 | 26.4 (24.2–29.0) | 2820 | 26.4 (24.3–29.1) | 2491 |
0.04
|
Energy intake (kilocalories/day) | 1996 (1653–2392) | 12,589 | 2001 (1671–2396) | 3239 | 1984 (1654–2391) | 3951 | 1982 (1625–2371) | 2868 | 2021 (1657–2416) | 2531 | 0.06 |
Diet quality score | 7 (5–8) | 12,589 | 7 (6–8) | 3239 | 7 (5–8) | 3951 | 7 (5–8) | 2868 | 7 (6–8) | 2531 | 0.63 |
N
| % |
N
| % |
N
| % |
N
| % |
N
| % | ||
---|---|---|---|---|---|---|---|---|---|---|---|
Sex | |||||||||||
Men | 5306 | 42.1 | 1391 | 43.0 | 1679 | 42.5 | 1181 | 41.18 | 1055 | 41.7 | 0.50 |
Women | 7283 | 57.9 | 1848 | 57.0 | 2272 | 57.5 | 1687 | 58.82 | 1476 | 58.3 | |
Education | |||||||||||
Primary | 1695 | 13.6 | 410 | 12.8 | 550 | 14.0 | 409 | 14.35 | 326 | 13.0 | < 0.01 |
Lower | 5189 | 41.6 | 1370 | 42.6 | 1553 | 39.7 | 1196 | 41.96 | 1070 | 42.8 | |
Intermediate | 3626 | 29.0 | 911 | 28.4 | 1128 | 28.8 | 828 | 29.05 | 759 | 30.4 | |
Higher | 1968 | 15.8 | 521 | 16.2 | 685 | 17.5 | 417 | 14.63 | 345 | 13.8 | |
Smoking status | |||||||||||
Never | 4031 | 32.1 | 1046 | 32.5 | 1261 | 32.0 | 908 | 31.76 | 816 | 32.5 | 0.42 |
Ever | 5879 | 46.9 | 1537 | 47.8 | 1855 | 47.0 | 1345 | 47.04 | 1142 | 45.4 | |
Current | 2626 | 21.0 | 635 | 19.7 | 829 | 21.0 | 606 | 21.20 | 556 | 22.1 | |
Prevalent diseasesb | |||||||||||
Yes | 2155 | 17.1 | 590 | 18.2 | 692 | 17.5 | 476 | 16.60 | 397 | 15.7 | 0.06 |
No | 10434 | 82.9 | 2649 | 81.8 | 3259 | 82.5 | 2392 | 83.40 | 2134 | 84.3 |
Seasonality of diet quality and daily intake of food groups
Outcome | Model | Seasonal variation* | 95% Confidence interval | Mean daily score/intake | Seasonal variation in percentagesa | Peak | Nadir |
---|---|---|---|---|---|---|---|
Diet quality score (0–14) | Model 1 | 0.12 |
0.03–0.21
| ||||
Model 2 | 0.10 |
0.01–0.18
| 6.72 | 1.49 | 19-Dec | 19-Jun | |
Kilocalories/day | Model 1 | 45.93 |
17.92–73.95
| ||||
Model 2 | 46.03 |
18.27–73.80
| 2067.43 | 2.23 | 29-Nov | 30-May | |
Food groups | |||||||
Vegetables (g/day) | Model 1 | 4.67 | − 2.19–11.54 | ||||
Model 2 | 4.81 | − 1.96–11.58 | 210.09 | 2.29 | 1-Sep | 2-Mar | |
Fruits (g/day) | Model 1 | 6.57 | − 5.360–18.50 | ||||
Model 2 | 3.18 | − 8.63–14.99 | 284.84 | 1.12 | 3-Dec | 4-Jun | |
Whole grain (g/day) | Model 1 | 2.95 | − 0.37–6.27 | ||||
Model 2 | 2.95 | − 0.37–6.27 | 125.36 | 2.35 | 12-Feb | 12-Aug | |
Legumes (g/day) | Model 1 | 3.52 |
2.62–4.42
| ||||
Model 2 | 3.51 |
2.61–4.41
| 9.09 | 38.61 | 30-Dec | 30-Jun | |
Nuts (g/day) | Model 1 | 0.82 |
0.20–1.45
| ||||
Model 2 | 0.78 |
0.16–1.41
| 8.25 | 9.45 | 25-Jan | 26-Jul | |
Dairy (g/day) | Model 1 | 16.95 |
5.03–28.87
| ||||
Model 2 | 17.52 |
5.60–29.44
| 365.65 | 4.79 | 17-Jun | 16-Dec | |
Fish (g/day) | Model 1 | 1.45 |
0.57–2.33
| ||||
Model 2 | 1.52 |
0.64–2.40
| 14.82 | 10.26 | 1-Jun | 30-Nov | |
Tea (mL/day) | Model 1 | 21.48 |
9.21–33.76
| ||||
Model 2 | 19.82 |
7.65–32.00
| 288.42 | 6.87 | 9-Feb | 9-Aug | |
Whole grain ratio | Model 1 | 0.59 | − 0.66–1.83 | ||||
Model 2 | 0.50 | − 0.75–1.75 | 68.54 | 0.73 | 10-Oct | 10-Apr | |
Unsaturated fat and oil ratio | Model 1 | 0.45 | − 1.00–1.91 | ||||
Model 2 | 0.32 | − 1.16–1.79 | 52.41 | 0.61 | 19-Feb | 19-Aug | |
Red and processed meat (g/day) | Model 1 | 2.11 | − 0.26–4.47 | ||||
Model 2 | 2.43 |
0.11–4.75
| 89.70 | 2.71 | 4-Nov | 6-May | |
Sugar-containing beverages (mL/day) | Model 1 | 13.01 |
7.22–18.80
| ||||
Model 2 | 12.96 |
7.16–18.77
| 75.52 | 17.16 | 1-Jun | 1-Dec | |
Alcohol (g/day) | Model 1 | 0.41 | − 0.25–1.07 | ||||
Model 2 | 0.34 | − 0.31–0.99 | 11.47 | 2.96 | 16-Jun | 16-Dec | |
Salt (mg/day) | Model 1 | 84.87 |
18.37–151.38
| ||||
Model 2 | 80.70 |
14.50–146.90
| 5658.87 | 1.43 | 5-Feb | 5-Aug |
Outcome | Seasonal variation* | 95% Confidence interval | %a |
---|---|---|---|
Diet quality score | 0.10 |
0.01–0.18
| |
Diet quality score excluding | |||
Vegetables | 0.12 |
0.04–0.20
| + 20 |
Fruit | 0.06 | − 0.02–0.13 | − 40 |
Whole grain products | 0.10 |
0.02–0.18
| 0 |
Legumes | 0.02 | − 0.06–0.10 | − 80 |
Nuts | 0.07 | − 0.01–0.16 | − 30 |
Dairy | 0.13 |
0.05–0.21
| + 30 |
Fish | 0.11 |
0.03–0.19
| + 10 |
Tea | 0.08 | − 0.00–0.17 | − 20 |
Whole grain ratio | 0.09 |
0.01–0.17
| − 10 |
Unsaturated fat and oil ratio | 0.10 |
0.02–0.18
| 0 |
Red and processed meat | 0.11 |
0.03–0.20
| + 10 |
Sugar-containing beverages | 0.07 | − 0.01–0.15 | − 30 |
Alcohol | 0.09 |
0.01–0.17
| − 10 |
Salt | 0.11 |
0.03–1.19
| + 10 |