Table 1.
Mean CRP and fibrinogen levels by gender, SEP and health-related lifestyle indicators across different agesa.
| Age groups | ||||||
|---|---|---|---|---|---|---|
| 25–34 (n = 964) | 35–49 (n = 2357) | 50–64 (n = 2516) | 65–79 (n = 1771) | 80 + (n = 335) | Total sample (n = 7943) | |
| Panel A. Mean CRP (mg/L) | ||||||
| Gender | ||||||
| Males | 1.373 | 1.786 | 2.028 | 2.192 | 2.533 | 1.872 |
| Females | 1.962 | 1.997 | 2.254 | 2.459 | 2.390 | 2.163 |
| % CRP difference [p-value for no differences]b | 42.9% [0.000] | 11.8% [0.009] | 11.1% [0.005] | 12.2% [0.008] | −5.6% [0.542] | 15.5% [0.000] |
| p-value for between age groups equalityc | 0.005 | |||||
| Equivalised household income (in tertiles) | ||||||
| High household income | 1.490 | 1.593 | 1.931 | 2.101 | 2.591 | 1.804 |
| Middle household income | 1.775 | 1.942 | 2.052 | 2.401 | 2.524 | 2.048 |
| Low household income | 1.704 | 2.158 | 2.449 | 2.490 | 2.254 | 2.213 |
| % CRP difference [p-value for no differences]b | 14.4% [0.147] | 35.4% [0.000] | 26.8% [0.000] | 18.5% [0.004] | −13% [0.234] | 22.7% [0.000] |
| p-value for between age groups equalityc | 0.000 | |||||
| Educational attainment | ||||||
| Degree | 1.594 | 1.574 | 1.791 | 1.756 | 2.075 | 1.656 |
| Other higher degree | 1.804 | 2.001 | 2.035 | 2.085 | 2.430 | 2.009 |
| A-level | 1.521 | 1.921 | 2.100 | 2.356 | 3.159 | 1.952 |
| O-level/basic qualifications | 1.835 | 2.098 | 2.114 | 2.312 | 2.129 | 2.100 |
| No qualifications | 1.437 | 2.102 | 2.772 | 2.676 | 2.596 | 2.556 |
| % CRP difference [p-value for no differences]b | −9.8% [0.539] | 33.5% [0.000] | 54.8% [0.000] | 52.4% [0.000] | 25.1% [0.454] | 54.3% [0.000] |
| p-value for between age groups equalityc | 0.000 | |||||
| Body Mass Index | ||||||
| 1st tertile | 1.245 | 1.172 | 1.398 | 1.519 | 1.858 | 1.328 |
| 2nd tertile | 1.532 | 1.807 | 1.899 | 2.212 | 2.759 | 1.917 |
| 3rd tertile | 2.625 | 2.714 | 2.947 | 3.020 | 2.725 | 2.837 |
| % CRP difference [p-value for no differences]b | 111% [0.000] | 131% [0.000] | 111% [0.000] | 98.8% [0.000] | 46.7% [0.001] | 113.6% [0.000] |
| p-value for between age groups equalityc | 0.001 | |||||
| Smoking status | ||||||
| Current smokers | 1.717 | 2.307 | 2.705 | 2.792 | 2.918 | 2.310 |
| Ex-smokers | 1.756 | 1.805 | 2.003 | 2.421 | 2.681 | 2.060 |
| Never smokers | 1.554 | 1.744 | 1.978 | 2.092 | 2.164 | 1.849 |
| % CRP difference [p-value for no differences]b | −9.5% [0.218] | −24.4% [0.000] | −26.9% [0.000] | −25.1% [0.000] | −25.8% [0.060] | −20.0% [0.000] |
| p-value for between age groups equalityc | 0.000 | |||||
| Sports activities | ||||||
| Sports participation | 1.642 | 1.732 | 1.894 | 1.947 | 2.542 | 1.789 |
| No sports participation | 1.685 | 2.098 | 2.314 | 2.531 | 2.435 | 2.231 |
| % CRP difference [p-value for no differences]b | 2.62% [0.734] | 21.1% [0.000] | 22.2% [0.000] | 29.9% [0.000] | −4.21% [0.719] | 24.71% [0.000] |
| p-value for between age groups equalityc | 0.002 | |||||
| # of days walking | ||||||
| 0 | 1.837 | 2.138 | 2.527 | 2.701 | 2.506 | 2.349 |
| 1–5 | 1.671 | 1.760 | 1.971 | 2.297 | 2.654 | 1.913 |
| 5–15 | 1.434 | 1.859 | 2.053 | 2.204 | 2.215 | 1.875 |
| 16+ | 1.611 | 1.822 | 1.964 | 1.956 | 2.123 | 1.856 |
| % CRP difference [p-value for no differences]b | −12.3% [0.097] | −14.8% [0.020] | −22.3% [0.000] | −27.6% [0.000] | −15.3% [0.296] | −21.0% [0.000] |
| p-value for between age groups equalityc | 0.090 | |||||
| Five fruits/vegetables per day | ||||||
| Reported | 1.881 | 1.625 | 1.891 | 2.064 | 2.427 | 1.882 |
| Not reported | 1.618 | 1.963 | 2.227 | 2.441 | 2.462 | 2.061 |
| % CRP difference [p-value for no differences]b | −14.0% [0.120] | 20.8% [0.000] | 17.8% [0.000] | 18.3% [0.000] | 1.4% [0.903] | 9.5% [0.001] |
| p-value for between age groups equalityc | 0.003 | |||||
| Non-full fat milk | ||||||
| Reported | 1.661 | 1.841 | 2.133 | 2.307 | 2.507 | 2.006 |
| Not reported | 1.637 | 2.246 | 2.234 | 2.534 | 2.182 | 2.126 |
| % CRP difference [p-value for no differences]b | -1.4% [0.877] | 22.0% [0.000] | 4.7% [0.433] | 9.8% [0.161] | -13% [0.308] | 6% [0.060] |
| p-value for between age groups equalityc | 0.044 | |||||
| Non-White bread | ||||||
| Reported | 1.705 | 1.754 | 2.036 | 2.184 | 2.340 | 1.934 |
| Not reported | 1.583 | 2.222 | 2.398 | 2.688 | 2.741 | 2.211 |
| % CRP difference [p-value for no differences]b | -7.2% [0.319] | 26.7% [0.000] | 17.8% [0.000] | 23.1% [0.000] | 17.1% [0.118] | 14.3% [0.000] |
| p-value for between age groups equalityc | 0.000 | |||||
| Panel B. Mean fibrinogen (g/L) | ||||||
| Gender | ||||||
| Males | 2.368 | 2.613 | 2.733 | 2.883 | 2.981 | 2.659 |
| Females | 2.574 | 2.675 | 2.857 | 2.971 | 3.092 | 2.780 |
| % fibrinogen difference [p-value for no differences]b | 8.7% [0.000] | 2.4% [0.005] | 4.5% [0.000] | 3.1% [0.000] | 3.7% [0.054] | 4.6% [0.000] |
| p-value for between age groups equalityc | 0.000 | |||||
| Equivalised household income (in tertiles) | ||||||
| High household income | 2.380 | 2.555 | 2.738 | 2.881 | 3.020 | 2.651 |
| Middle household income | 2.479 | 2.664 | 2.792 | 2.938 | 3.055 | 2.730 |
| Low household income | 2.541 | 2.718 | 2.860 | 2.968 | 3.048 | 2.783 |
| % fibrinogen difference [p-value for no differences]b | 6.8% [0.000] | 6.4% [0.000] | 4.5% [0.000] | 3.5% [0.015] | 0.93% [0.863] | 5.0% [0.000] |
| p-value for between age groups equality c | 0.040 | |||||
| Educational attainment | ||||||
| Degree | 2.431 | 2.531 | 2.685 | 2.837 | 2.986 | 2.573 |
| Other higher degree | 2.458 | 2.630 | 2.784 | 2.836 | 2.978 | 2.695 |
| A-level | 2.433 | 2.667 | 2.795 | 2.918 | 2.999 | 2.681 |
| O-level/basic qualifications | 2.532 | 2.713 | 2.810 | 2.944 | 3.017 | 2.768 |
| No qualifications | 2.608 | 2.800 | 2.921 | 2.994 | 3.091 | 2.940 |
| % fibrinogen difference [p-value for no differences]b | 7.3% [0.002] | 10.6% [0.000] | 8.8% [0.000] | 5.5% [0.000] | 3.5% [0.111] | 14.3% [0.000] |
| p-value for between age groups equalityc | 0.109 | |||||
| Body Mass Index | ||||||
| 1st tertile | 2.350 | 2.486 | 2.688 | 2.860 | 3.029 | 2.577 |
| 2nd tertile | 2.438 | 2.607 | 2.758 | 2.891 | 3.086 | 2.700 |
| 3rd tertile | 2.736 | 2.844 | 2.917 | 3.014 | 2.984 | 2.891 |
| % fibrinogen difference [p-value for no differences]b | 16.4% [0.000] | 14.4% [0.000] | 8.5% [0.000] | 5.4% [0.000] | -1.5% [0.622] | 12.2% [0.000] |
| p-value for between age groups equalityc | 0.000 | |||||
| Smoking status | ||||||
| Current smokers | 2.505 | 2.788 | 3.001 | 3.146 | 3.284 | 2.810 |
| Ex-smokers | 2.474 | 2.613 | 2.720 | 2.906 | 3.006 | 2.719 |
| Never smokers | 2.436 | 2.592 | 2.758 | 2.890 | 3.049 | 2.679 |
| % fibrinogen difference [p-value for no differences]b | −2.8% [0.053] | −7.0% [0.000] | −8.1% [0.000] | −8.1% [0.000] | −7.2% [0.557] | −4.7% [0.000] |
| p-value for between age groups equalityc | 0.000 | |||||
| Sports activities | ||||||
| Sports participation | 2.463 | 2.601 | 2.722 | 2.850 | 2.982 | 2.632 |
| No sports participation | 2.474 | 2.700 | 2.848 | 2.970 | 3.055 | 2.802 |
| % fibrinogen difference [p-value for no differences]b | 0.4% [0.736] | 3.8% [0.000] | 4.6% [0.000] | 4.2% [0.000] | 2.4% [0.309] | 6.5% [0.000] |
| p-value for between age groups equalityc | 0.015 | |||||
| # of days walking | ||||||
| 0 | 2.494 | 2.699 | 2.865 | 3.009 | 3.090 | 2.814 |
| 1–5 | 2.439 | 2.614 | 2.779 | 2.917 | 2.993 | 2.681 |
| 5–15 | 2.446 | 2.625 | 2.782 | 2.904 | 2.786 | 2.674 |
| 16+ | 2.482 | 2.647 | 2.755 | 2.857 | 2.989 | 2.694 |
| % fibrinogen difference [p-value for no differences]b | −0.5% [0.860] | −1.9% [0.155] | −3.8% [0.000] | −5.1% [0.000] | −3.3% [0.021] | −4.3% [0.000] |
| p-value for between age groups equalityc | 0.106 | |||||
| Five or more fruits/vegetables per day | ||||||
| Reported | 2.441 | 2.609 | 2.763 | 2.903 | 3.007 | 2.723 |
| Not reported | 2.472 | 2.654 | 2.808 | 2.940 | 3.050 | 2.721 |
| % fibrinogen difference [p-value for no differences]b | 1.3% [0.471] | 1.7% [0.107] | 1.6% [0.050] | 1.3% [0.182] | 1.4% [0.537] | -0.1% [0.926] |
| p-value for between age groups equalityc | 0.997 | |||||
| Non-full fat milk | ||||||
| Reported | 2.463 | 2.637 | 2.796 | 2.932 | 3.046 | 2.722 |
| Not reported | 2.486 | 2.699 | 2.806 | 2.905 | 3.018 | 2.717 |
| % fibrinogen difference [p-value for no differences]b | 0.9% [0.577] | 2.4% [0.049] | 0.4% [0.748] | -0.9% [0.505] | -0.9% [0.724] | -0.2% [0.744] |
| p-value for between age groups equalityc | 0.471 | |||||
| Non-white bread | ||||||
| Reported | 2.482 | 2.605 | 2.783 | 2.911 | 3.018 | 2.700 |
| Not reported | 2.445 | 2.736 | 2.830 | 2.973 | 3.100 | 2.744 |
| % fibrinogen difference [p-value for no differences]b | −1.5% [0.245] | 5% [0.000] | 1.7% [0.036] | 2.1% [0.025] | 2.7% [0.183] | 1.7% [0.012] |
| p-value for between age groups equalityc | 0.000 | |||||
aAge groups selected to reflect different life stages. Bivariate analyses were adjusted to account for sample weights.
bPercentage difference in CRP and fibrinogen levels were calculated comparing the mean biomarker levels between gender, SEP and health-related lifestyle indicators. The lowest and the highest categories were used for the case of these variables that had more than two categories and expressed changes as a percentage of the mean CRP or fibrinogen levels of the first -as presented in the table- category of each variable. P-values for absence of differences in CRP and Fibrinogen levels by gender, SEP groups and ealth-related lifestyle indicators are calculated using chi-squared two-tailed tests (for each of the age groups and for the whole sample).
cThe presence of systematic heterogeneity in the association between CRP/fibrinogen and the other variables (gender, SEP measures and lifestyle indicators) across age groups was tested by two-tailed F-tests for the joint significance of interaction terms of the (categories of the) latter variables with age categories.