TABLE 2.

Associations of long-term diet quality and intakes of major food groups with gut microbiome α-diversity in the Shanghai Women's and Men's Health Studies¹

	Linear regression coefficient (SE) of dietary variables with the Shannon diversity index
Dietary variables	Quintile 2	Quintile 3	Quintile 4	Quintile 5	1-SD increment	P value
Healthy diet score (average)	0.068 (0.042)	0.044 (0.042)	0.063 (0.043)	0.093 (0.043)2	0.029 (0.014)	0.03
Healthy diet score (most recent)	0.057 (0.042)	0.020 (0.043)	0.064 (0.043)	0.074 (0.043)	0.035 (0.014)	0.01
Fruit	0.042 (0.043)	0.006 (0.043)	0.082 (0.043)	0.043 (0.044)	0.0005 (0.014)	0.97
Vegetables	0.050 (0.042)	0.069 (0.042)	0.063 (0.043)	0.034 (0.043)	0.008 (0.014)	0.55
Dairy products	−0.035 (0.042)	−0.003 (0.043)	0.030 (0.043)	0.024 (0.045)	0.013 (0.014)	0.36
Fish and seafood	0.045 (0.042)	0.098 (0.042)2	0.111 (0.043)2	0.103 (0.043)2	0.022 (0.014)	0.11
Nuts and legumes	0.004 (0.042)	0.012 (0.042)	0.052 (0.043)	−0.030 (0.043)	−0.021 (0.014)	0.12
Refined grains	0.071 (0.042)	0.035 (0.042)	0.007 (0.043)	−0.014 (0.043)	−0.003 (0.014)	0.82
Red meat	0.0001 (0.042)	0.056 (0.042)	0.067 (0.043)	0.006 (0.043)	0.005 (0.014)	0.73
Processed meat	−0.004 (0.038)	−0.064 (0.038)	−0.120 (0.042)2	−0.040 (0.052)	−0.024 (0.022)	0.28

¹Dietary variables were modeled as sex-specific quintiles with the lowest quintile as the referent group and continuous variables as per SD increase. The general linear model was adjusted for age at stool sample collection, sex, income, smoking status, alcohol drinking status, leisure-time physical activity, total energy intake, BMI, history of hypertension, and sequencing depth. P values for the associations between a 1-SD increase in dietary variables and the Shannon index are shown.

² P < 0.05 for each quintile compared with the lowest quintile.