Gut microbiota with inflammatory immune markers
The list of all microbial taxa assessed for their association with inflammatory immune markers (NLR, PLR, and SII) after adjusting for co-factors are shown in Fig. 1a, Fig. 2, and Table S1. There were 95 microbial families and genera associated with inflammatory immune markers NLR, PLR, and SII (Fig. 1a, Fig. 2, and Table S2). In total, 61 taxa had a positive association and 34 taxa had inverse association with the immune markers NLR, PLR, and SII (Fig. 1a, Fig. 2, and Table S2). Most of these microbial families and genera were from the phylum Firmicutes while the other were from phylum Actinobacteriota and Bacteroidota (Table S2). Thirty-three microbial taxa were positively associated with a single immune marker: twenty taxa with NLR; six with PLR, and seven with SII. Increased levels of all three immune markers were associated with increased abundance of the order of Lactobacillales, genus Lactonifactor and species, while decreased levels of all these three biomarkers were associated with decreased abundance of genus Fusicatenibacter, species shahii and species saccharivorans (Table S3). Twenty-five microbial taxa were positively associated with two immune markers (Table S4).
Gut microbiota with white blood cells
The complete list of microbial taxa evaluated for their association with WBCs (lymphocytes, granulocytes, and platelets) after adjusting for co-factors are shown in (Fig. 1b, Fig. 3, and Table S5). We observed 120 microbial families and genera associated with lymphocytes, granulocytes, and platelets after removing duplicates (Fig. 1b, Fig. 3, and Table S6). Importantly, we observed three microbial taxa including family Streptococcaceae, order Lactobacillales, and genus Streptococcus that were inversely associated with lymphocytes (FDR ≤ 0.05). All these three microbial families and genera were from phylum Firmicutes (Fig. 1b, Fig. 3, and Table S6). Overall, 70 taxa had a positive association and 50 taxa had inverse association with lymphocytes, granulocytes, and platelets. 66 microbial taxa were positively associated with a single WBC: 41 taxa with granulocytes; 20 with lymphocytes, and five with platelets. Four microbial taxa were positively associated with two WBCs (Table S7). The overlap of WBCs and immune markers for the gut-microbial taxa is shown in Fig. 4.
Risk of cancer development
In total, 961 individuals (11.9%) developed cancer during follow-up, namely cancers of colorectal (n = 166, 17.3%), breast (n = 127, 13.2%), lung (n = 121, 12.6%), pancreas (n = 28, 2.9%), other cancers (n = 497, 51.7%) and melanoma (n = 22, 2.3%). Higher baseline SII levels appeared to be specifically associated with an increased risk of lung cancer after adjusting for age, sex, BMI, and study cohort (HR: 1.65 (95% CI 1.10–2.46, (P-value ≤ 0.05) (Table 2). This association disappeared after additional adjustment for smoking (HR: 1.46 (95% CI; 0.96–2.22, P-value = 0.07) (Table 3). No association was observed between NLR and PLR levels with the incidence of any of the cancers included in this analysis (Table 2 and Table 3). In addition, high lymphocytes and granulocytes count showed a significant association with an increased risk of lung cancer after adjusting for age, sex, BMI, and study cohort with lymphocytes (HR: 1.38 [95% CI; 1.15–1.65, P-value ≤ 0.05]) and granulocytes (HR: 1.69 [95% CI; 1.40–2.03, P-value ≤ 0.05]) (Table 4). This association disappeared for lymphocytes after additional adjustment for smoking (HR: 1.19 (95% CI; 0.97–1.46, P-value = 0.08) (Table S8).
Table 2
Multivariate Cox regression analysis for the association between baseline PLR, NLR, and SII level with the development of cancer in Model 1.
Cancer type | N | NLR | PLR | SII |
Hazard Ratio (95% CI)1 | P-value | Hazard Ratio (95% CI)1 | P-value | Hazard Ratio (95% CI)1 | P-value |
Colorectal | 163 | 1.12 (0.74–1.69) | 0.58 | 1.12 (0.71–1.77) | 0.60 | 1.28 (0.92–1.79) | 0.13 |
Breast | 124 | 0.98 (0.61–1.58) | 0.95 | 1.24 (0.72–2.13) | 0.42 | 1.05 (0.70–1.55) | 0.80 |
Lung | 110 | 1.59 (0.96–2.62) | 0.06 | 0.64 (0.37–1.09) | 0.10 | 1.65 (1.10–2.46) | 0.01 |
Pancreas | 25 | 1.28 (0.45–3.66) | 0.63 | 0.80 (0.25–2.57) | 0.71 | 1.03 (0.43–2.43) | 0.93 |
Melanoma | 21 | 1.93 (0.61–6.07) | 0.25 | 2.07 (0.58–7.40) | 0.25 | 2.12 (0.84–5.31) | 0.10 |
1Adjusted for age (year), sex, BMI, and RS-cohort. |
Table 3
Multivariate Cox regression analysis for the association between baseline PLR, NLR, and SII level with the development of cancer in Model 2.
Cancer type | N | NLR | PLR | SII |
Hazard Ratio (95% CI)1 | P-value | Hazard Ratio (95% CI)1 | P-value | Hazard Ratio (95% CI)1 | P-value |
Colorectal | 156 | 1.13 (0.74–1.73) | 0.56 | 1.05 (0.66–1.67) | 0.83 | 1.26 (0.90–1.78) | 0.17 |
Breast | 124 | 0.97 (0.60–1.57) | 0.91 | 1.30 (0.75–2.24) | 0.34 | 1.04 (0.70–1.54) | 0.83 |
Lung | 108 | 1.36 (0.81–2.29) | 0.23 | 0.91 (0.52–1.60) | 0.75 | 1.46 (0.96–2.22) | 0.07 |
Pancreas | 24 | 1.17 (0.40–3.43) | 0.77 | 0.88 (0.26–2.93) | 0.84 | 0.97 (0.40–2.34) | 0.95 |
Melanoma | 20 | 1.86 (0.58–5.98) | 0.29 | 1.99 (0.52–7.51) | 0.30 | 2.23 (0.86–5.77) | 0.09 |
1Adjusted for age (year), sex, BMI, RS-cohort, and smoking. |
Table 4
Multivariate Cox regression analysis for the association between white blood cell count with the development of cancer based on Model 1.
Cancer type | N | Lymphocytes | Granulocytes | Platelets |
Hazard Ratio (95% CI)1 | P-value | Hazard Ratio (95% CI)1 | P-value | Hazard Ratio (95% CI)1 | P-value |
Colorectal | 163 | 1.07 (0.91–1.25) | 0.40 | 1.12 (0.95–1.32) | 0.15 | 1.15 (0.98–1.36) | 0.08 |
Breast | 124 | 0.95 (0.78–1.15) | 0.64 | 0.95 (0.79–1.14) | 0.63 | 1.05 (0.87–1.28) | 0.56 |
Lung | 110 | 1.38 (1.15–1.65) | 3×10− 4 | 1.69 (1.40–2.03) | 3.2×10− 8 | 1.21 (0.99–1.48) | 0.057 |
Pancreas | 25 | 0.98 (0.64–1.49) | 0.93 | 1.10 (0.74–1.65) | 0.62 | 0.88 (0.58–1.32) | 0.54 |
Melanoma | 21 | 0.94 (0.59–1.48) | 0.79 | 1.29 (0.82–2.04) | 0.25 | 1.37 (0.86–2.18) | 0.18 |
1Adjusted for age (year), sex, BMI, RS-cohort. |
Effects of smoking
The results for the association between immune markers (NLR, PLR, SII) and WBCs with smoking status and BMI are shown in Table 5 and Table S9, respectively. Since the BMI and smoking turned out to be major drivers of association between immune markers and WBCs with cancer development, we assessed the individual role of BMI and smoking in blood levels of immune markers (NLR, PLR, and SII) and WBCs by linear regression adjusted for age and sex. All three immune markers and WBCs were significantly associated with smoking after adjusting for age and sex, namely NLR (0.08, 95% CI; 0.056–0.106, P-value = 1.99×10–10), PLR (-0.13, 95% CI; [(-0.156) - (-0.111)], P-value < 2×10–16), SII (0.11, 95% CI; 0.083–0.144, P-value = 2.93×10–13), lymphocytes (0.54, 95% CI; 0.480–0.605, P-value < 2×10–16), granulocytes (0.75, 95% CI; 0.693–0.819, P-value < 2×10–16), and platelets (0.12, 95% CI; 0.062–0.187, P-value = 8.17×10− 5). The levels of PLR and all three WBCs correlated with those of BMI after adjusting for age and sex, with PLR (-0.008, 95% CI; [(-0.010) - (-0.006)], P-value < 2×10–16), lymphocytes (0.02, 95% CI; 0.018–0.028, P-value < 2×10–16), granulocytes (0.02, 95% CI; 0.022–0.032, P-value < 2×10–16), and platelets (-0.005, 95% CI; [(-0.010) - (-0.0004)], P-value = 0.03).
Table 5
Linear regression analysis for the association between baseline PLR, NLR, and SII level with smoking status and BMI.
Model | Variable | NLR | PLR | SII |
Hazard Ratio (95% CI)1 | P-value | Hazard Ratio (95% CI)1 | P-value | Hazard Ratio (95% CI)1 | P-value |
Smoking | Former smoker | 0.01 (-0.002–0.036) | 0.082 | -0.003(-0.020–0.014) | 0.718 | 0.02 (-0.0003–0.0467) | 0.053 |
| Current smoker | 0.08 (0.056–0.106) | 1.99 × 10− 10 | -0.13 (-0.156 - -0.111) | < 2 × 10− 16 | 0.11 (0.083–0.144) | 2.93×10− 13 |
BMI | BMI | 0.001 (-9.260–0.003) | 0.062 | -0.008 (-0.010 - -0.006) | < 2 × 10− 16 | 0.0005 (-0.001–0.002) | 0.662 |
1Adjusted for age (year) and sex. |
In the stratified analysis, 260 (9.8%) individuals among non-smokers (n = 2,664) developed cancer during follow-up, viz., colorectal cancers (n = 56, 21.5%), breast cancers (n = 50, 19.2%), lung cancers (n = 13, 5%), pancreatic cancers (n = 11, 4.2%), melanoma (n = 11, 4.2%), and other cancers (n = 119, 45.8%). Baseline characteristics of the respective cohorts for non-smokers are shown in Table S10. In smokers (n = 5,426), 701 individuals (12.9%) developed cancer during follow-up viz., cancers of colon and rectum (n = 110, 15.7%), breast (n = 77, 11%), lung (n = 108, 15.4%), pancreas (n = 17, 2.4%), melanoma (n = 11, 1.6%) and other cancers (n = 378, 53.9%). The characteristics of each cohort for smokers are shown in Table S13. We observed a significant association between higher counts of granulocytes and platelets with increased risk of colorectal cancer (HR: 1.41 [95% CI; 1.05–1.89, P-value ≤ 0.05], and HR: 1.59 [95% CI; 1.17–2.17, P-value ≤ 0.05], respectively) and between higher count of granulocytes with increased risk of lung cancer (HR: 1.82 [95% CI; 1.00-3.32, P-value ≤ 0.05]) in non-smokers group after adjusting for age, sex, BMI, and study cohort (Table S11). However, we found no effect for NLR, PLR, and SII on the risk of lung cancers, or colorectal, pancreatic, breast cancer, and melanoma in the non-smokers group after adjusting for age, sex, BMI, and study cohort (Table S12). We observed a significant association between lymphocytes and granulocytes with increased risk of lung cancer in smokers after adjusting for age, sex, BMI, and study cohort (HR: 1.33 [95% CI; 1.09–1.62, P-value = 3.53×10− 3], and HR: 1.57 [95% CI; 1.28–1.92, P-value = 9.61×10− 6], respectively) (Table 6). Moreover, higher baseline SII levels were associated with increased risk of lung cancer in smokers after adjusting for age, sex, BMI, and study cohort (HR: 1.61 [95% CI; 1.05–2.47, P-value ≤ 0.05]) (Table S14).
Table 6
Multivariate Cox regression analysis for the association between lymphocytes, granulocytes, and platelets counts with the development of cancer in smokers.
Cancer type | N | Lymphocytes | Granulocytes | Platelets |
Hazard Ratio (95% CI)1 | P-value | Hazard Ratio (95% CI)1 | P-value | Hazard Ratio (95% CI)1 | P-value |
Colorectal | 109 | 0.96 (0.79–1.18) | 0.75 | 1.00 (0.82–1.23) | 0.92 | 0.99 (0.81–1.20) | 0.93 |
Breast | 75 | 0.96 (0.75–1.23) | 0.75 | 0.91 (0.72–1.15) | 0.44 | 1.08 (0.83–1.39) | 0.54 |
Lung | 98 | 1.33 (1.09–1.62) | 3.53×10− 3 | 1.57 (1.28–1.92) | 9.61×10− 6 | 1.22 (0.99–1.50) | 0.057 |
Pancreas | 17 | 0.85 (0.51–1.42) | 0.54 | 0.83 (0.52–1.35) | 0.47 | 0.83 (0.53–1.31) | 0.44 |
Melanoma | 10 | 0.70 (0.35–1.37) | 0.30 | 1.15 (0.60–2.22) | 0.66 | 1.20 (0.60–2.38) | 0.59 |
1Adjusted for age (year), sex, BMI, RS-cohort. |