Drinking plain water is associated with decreased risk of depression and anxiety in adults: Results from a large cross-sectional study

Table 1 General characteristic of participants across categories of plain water consumption

Variables	Plain water drinking			P value1
	< 2 glasses/d	2-5 glasses/d	≥ 5 glasses/d
Participants (n)	854	1764	709
Age (yr)2	37.2 ± 0.3	36.1 ± 0.2	34.8 ± 0.3	< 0.0001
BMI (kg/m2)2	24.7 ± 0.1	24.7 ± 0.10	25.5 ± 0.2	< 0.0001
Anxiety score2	4.0 ± 0.1	3.5 ± 0.10	3.0 ± 0.1	< 0.0001
Depression score2n (%)	6.8 ± 0.1	6.1 ± 0.09	5.3 ± 0.1	< 0.0001
Anxious	136 (16.2)	244 (14.1)	61 (8.7)	< 0.0001
Depressed	303 (36.0)	478 (27.7)	151 (21.6)	< 0.0001
Male	242 (28.3)	757 (42.9)	387 (54.6)	< 0.0001
Marital status				0.035
Married	680 (81.4)	1431 (82.9)	549 (78.8)
Single	135 (16.2)	271 (15.7)	139 (19.9)
Other	20 (2.4)	25 (1.4)	9 (1.3)
Anti-psychotic medicines use	56 (6.6)	91 (5.2)	39 (5.5)	0.342
Current smokers	147 (17.2)	243 (13.8)	70 (9.9)	< 0.0001
Moderately active and active	303 (39.6)	729 (45.7)	350 (56.1)	< 0.0001
Educational level				0.005
≤ 12 yr	333 (39.8)	633 (36.9)	301 (43.1)
12-16 yr	438 (52.4)	956 (55.6)	347 (49.7)
≥ 16 yr	65 (7.8)	129 (7.5)	50 (7.2)
FGID3 (%)	488 (57.1)	892 (50.6)	321 (45.3)	< 0.0001
Nutrients4
Energy (kcal/d)	2306.1 ± 30.1	2385.8 ± 20.7	2487.9 ± 34.7	0.001
Protein (% of total calorie)	84.3 ± 1.2	88.5 ± 0.8	93.2 ± 1.4	< 0.0001
Fat (% of total calorie)	95.5 ± 1.3	98.7 ± 0.9	103.1 ± 1.5	0.001
Carbohydrate (g/d)	285.3 ± 4.2	294.5 ± 2.9	306.3 ± 4.9	0.006
Fibre (g/d)	22.0 ± 0.2	22.5 ± 0.1	23.0 ± 0.2	0.003
Caffeine (mg/d)	106.7 ± 3.1	96.7 ± 2.2	96.0 ± 3.7	0.022
Magnesium (mg/d)	314.1 ± 4.3	327.2 ± 3.0	349.6 ± 5.0	< 0.0001
Thiamin (mg/d)	1.8 ± 0.03	1.8 ± 0.02	1.9 ± 0.03	0.062
Riboflavin (mg/d)	1.8 ± 0.03	1.9 ± 0.02	2.0 ± 0.03	< 0.0001
Pyridoxine (mg/d)	1.9 ± 0.03	2.0 ± 0.02	2.1 ± 0.03	< 0.0001
Folate (mg/d)	562.4 ± 5.8	573.8 ± 4.0	600.2 ± 6.7	0.801
Cobalamine (mg/d)	2.8 ± 0.05	3.0 ± 0.03	3.1 ± 0.05	< 0.0001
DHA (g/d)3	0.2 ± 0.01	0.2 ± 01	0.2 ± 0.01	< 0.0001
EPA (g/d)3	0.06 ± 0.003	0.1 ± 0.002	0.1 ± 0.003	< 0.0001
Food groups
Fruits (g/d)	285.8 ± 8.7	322.4 ± 6.0	351.1 ± 10.1	< 0.0001
Vegetables (g/d)	215.4 ± 4.8	241.4 ± 3.3	264.7 ± 5.5	< 0.0001
Nuts, legumes and soy (g/d)	55.5 ± 1.5	56.8 ± 1.0	60.9 ± 1.7	0.047
White meat (g/d)	59.4 ± 1.8	64.03 ± 1.2	67.5 ± 2.02	0.009
Red meat (g/d)	75.4 ± 1.8	78.4 ± 1.2	84.5 ± 2.06	0.004
Refined grains (g/d)	401.6 ± 7.1	390.7 ± 5.4	389.4 ± 9.11	0.473
Whole grains (g/d)	39.5 ± 2.9	40.8 ± 1.1	52.1 ± 3.40	0.007

¹Derived from one way ANOVA and chi-square test for continuous and categorical variables, respectively and analysis of covariance (ANCOVA) for nutrients and food groups;

²Values are means ± SEs;

³FGID defined as suffering from at least one of the following gastrointestinal disorders: Gastroesophageal Reflux, dyspepsia, irritable bowel syndrome and constipation;

⁴The nutrients were adjusted for age and body weight. DHA: Docosahexaenoic acid; EPA: Eicosa pentaenoic acid.

Table 2 General characteristics of participants based on categories of anxiety and depression n (%)

	Depression		P value1	Anxiety		P value1
	Yes (28%)	No (72%)		Yes (13.1%)	No (86.9%)
Age (yr)2	36.3 ± 0.3	36.1 ± 0.2	0.562	35.4 ± 0.2	36.3 ± 0.3	0.020
BMI (kg/m2)2	24.8 ± 0.1	24.9 ± 0.1	0.712	25.0 ± 0.2	24.9 ± 0.1	0.636
Male	285 (30.2)	1082 (46.0)	< 0.0001	117 (26.1)	1251 (43.9)	< 0.0001
Anti-psychotic medicines	106 (11.2)	76 (3.2)	< 0.0001	70 (15.6)	113 (4.0)	< 0.0001
Current smokers	164 (17.4)	290 (12.3)	< 0.0001	84 (18.8)	370 (13.0)	0.001
Moderately active and active	338 (39.7)	1028 (48.8)	< 0.0001	155 (38.5)	1212 (47.4)	0.001
Educational level			< 0.0001			< 0.0001
< 12 yr	153 (16.7)	236 (10.2)		84 (19.3)	306 (11.0)
12-16 yr	715 (78.1)	1876 (81.4)		337 (77.5)	2255 (80.9)
≥ 16 yr	48 (5.2)	194 (8.4)		14 (3.2)	228 (8.2)
Marital status			0.001			0.001
Married	733 (79.4)	1901 (82.4)		361 (83.2)	2274 (81.3)
Single	163 (17.7)	380 (16.5)		58 (13.4)	486 (17.4)
Other	27 (2.9)	26 (1.1)		15 (3.5)	38 (1.4)
FGID3	665 (70.5)	1022 (43.4)	< 0.0001	357 (79.7)	1329 (46.6)	< 0.0001
Water drinking			< 0.0001			< 0.0001
< 2 glasses/d	303 (32.5)	539 (23.1)		136 (30.8)	706 (25.0)
2-5 glasses/d	478 (51.3)	1246 (53.4)		244 (55.3)	1481 (52.4)
≥ 5 glasses/d	151 (16.2)	548 (23.5)		61 (13.8)	639 (22.6)

¹Derived from independent t-test and chi-square test for continuous and categorical variables, respectively;

²Values are means ± SEs or percent;

³FGID defined as suffering from at least one of the following gastrointestinal disorders: Gastroesophageal Reflux, dyspepsia, irritable bowel syndrome and constipation.

Table 3 Multivariable-adjusted ORs (and 95%CIs) for depression and anxiety across categories of plain water consumption in the whole population and stratified by sex

	Plain water drinking			P trend1
	< 2 glasses/d	2-5 glasses/d	≥ 5 glasses/d
Depression
Crude model	2.04 (1.62, 2.56)	1.39 (1.13, 1.71)	1 (reference)	< 0.0001
Model 12	1.75 (1.35, 2.26)	1.30 (1.02, 1.64)	1 (reference)	< 0.0001
Model 22	1.84 (1.37, 2.45)	1.39 (1.07, 1.80)	1 (reference)	< 0.0001
Model 32	1.84 (1.40, 2.49)	1.41 (1.07, 1.84)	1 (reference)	< 0.0001
Model 42	1.79 (1.32, 2.42)	1.37 (1.04, 1.80)	1 (reference)	< 0.0001
Anxiety
Crude model	2.02 (1.46, 2.78)	1.73 (1.29, 2.32)	1 (reference)	< 0.0001
Model 12	1.53 (1.07, 2.17)	1.44 (1.04, 1.99)	1 (reference)	0.026
Model 22	1.58 (1.06, 2.36)	1.60 (1.11, 2.30)	1 (reference)	0.029
Model 32	1.56 (1.03, 2.35)	1.63 (1.12, 2.40)	1 (reference)	0.066
Model 42	1.49 (0.98, 2.25)	1.58 (1.08, 2.30)	1 (reference)	0.109
Men (n = 1386)
Depression
Crude model	1.77 (1.19, 2.63)	1.37 (0.99, 1.90)	1 (reference)	0.004
Model 12	2.00 (1.26, 3.20)	1.45 (0.98, 2.13)	1 (reference)	0.003
Model 22	1.95 (1.18, 3.21)	1.59 (1.06, 2.38)	1 (reference)	0.008
Model 32	1.73 (1.02, 2.92)	1.54 (1.01, 2.36)	1 (reference)	0.037
Model 42	1.73 (1.02, 2.93)	1.54 (1.00, 2.36)	1 (reference)	0.040
Anxiety
Crude model	1.83 (0.97, 3.43)	2.01 (1.20, 3.34)	1 (reference)	0.041
Model 12	2.36 (1.17, 4.74)	1.55 (0.87, 2.78)	1 (reference)	0.016
Model 22	2.15 (1.02, 4.54)	1.59 (0.86, 2.95)	1 (reference)	0.042
Model 32	1.76 (0.81, 3.84)	1.55 (0.82, 2.94)	1 (reference)	0.147
Model 42	1.74 (0.80, 3.80)	1.52 (0.80, 2.88)	1 (reference)	0.161
Women (n = 1941)
Depression
Crude model	1.75 (1.30, 2.35)	1.26 (0.95, 1.67)	1 (reference)	<0.0001
Model 12	1.61 (1.17, 2.21)	1.21 (0.90, 1.63)	1 (reference)	0.001
Model 22	1.61 (1.16, 2.23)	1.21 (0.89, 1.65)	1 (reference)	0.002
Model 32	1.61 (1.15, 2.26)	1.22 (0.89, 1.67)	1 (reference)	0.003
Model 42	1.54 (1.09, 2.15)	1.18 (0.86, 1.63)	1 (reference)	0.007
Anxiety
Crude model	1.59 (1.08, 2.34)	1.42 (0.98, 2.05)	1 (reference)	0.026
Model 12	1.35 (0.89, 2.05)	1.41 (0.95, 2.07)	1 (reference)	0.264
Model 22	1.39 (0.91, 2.13)	1.44 (0.97, 2.15)	1 (reference)	0.233
Model 32	1.37 (0.88, 2.13)	1.44 (0.95, 2.18)	1 (reference)	0.288
Model 42	1.30 (0.83, 2.02)	1.40 (0.92, 2.12)	1 (reference)	0.420

¹Derived from a Mantel-Haenszel extension chi-square test;

²Model 1: Adjusted for age, sex (in the whole population), marital status, educational level, model 2: Further adjustment for BMI, smoking, physical activity, model 3: Additional control for functional gastrointestinal disorders (FGID) and anti-psychotic medicines, model 4: Further control for magnesium, riboflavin, pyridoxine, folate, cobalamin, DHA and EPA, energy, fibre and caffeine. DHA: Docosahexaenoic acid; EPA: Eicosa pentaenoic acid.