Table 1.
Characteristics of the study population from the NHANES) 2003–2006 (n=6,607)
| Hypertension | |||||
|---|---|---|---|---|---|
| Total (n=6,607) |
No (n=4,160) (67.8%) |
Yes (n=2,447) (32.2%) |
p-value | ||
| Age (years) a | 46.6±0.50 | 40.7±0.45 | 58.4±0.62 | <0.0001 | |
| Female (%) | 51.4 | 51.3 | 51.8 | 0.7536 | |
| Race/ethnicity (%) | |||||
| Non-Hispanic White | 75.2 | 74.2 | 77.2 | ||
| Non-Hispanic Black | 10.3 | 9.2 | 12.5 | <0.0001 | |
| Mexican American | 7.5 | 9.1 | 4.4 | ||
| Other Hispanic | 2.6 | 3.0 | 1.7 | ||
| Others | 4.5 | 4.6 | 4.2 | ||
| Education (%) | |||||
| Less than high school | 15.7 | 13.5 | 20.0 | <0.0001 | |
| High school | 25.1 | 23.8 | 27.5 | ||
| Greater than high school | 59.3 | 62.6 | 52.5 | ||
| Body mass index (kg/m2) a | 28.3±0.19 | 27.3±0.17 | 30.3±0.24 | <0.0001 | |
| Alcohol usage (%) | 72.0 | 76.3 | 63.4 | <0.0001 | |
| Smoking (%) | |||||
| Never | 50.2 | 52.1 | 46.2 | ||
| Former | 26.2 | 21.5 | 35.6 | <0.0001 | |
| Current | 23.6 | 26.4 | 18.2 | ||
| Cotinine (ng/ mL) b | 0.47 (0.35, 0.62) |
0.56 (0.40, 0.78) |
0.32 (0.24, 0.44) |
0.0004 | |
| Blood mercury (µg/L) b | 1.03 (0.95, 1.11) |
1.02 (0.94, 1.10) |
1.05 (0.94, 1.16) |
0.5060 | |
| Urinary creatinine (mg/dL)bc | 97.5 (93.6, 101) |
102 (96.6, 107) |
89.3 (84.0, 95.0) |
0.0021 | |
| Urinary mercury (ng/ mL) b c | 0.51 (0.47, 0.54) |
0.55 (0.50, 0.59) |
0.44 (0.39, 0.48) |
0.0014 | |
| Creatinine-corrected urinary mercury (ng/mg) b c | 0.52 (0.49, 0.55) |
0.54 (0.50, 0.57) |
0.49 (0.44, 0.54) |
0.0793 | |
| Systolic blood pressure (mmHg) a | 123.2±0.41 | 115.6±0.23 | 138.2±0.59 | <0.0001 | |
| Diastolic blood pressure (mmHg) a | 71.2±0.25 | 69.0±0.23 | 75.7±0.49 | <0.0001 | |
| Hypertensive medication (%) | 24.3 | - | 72.9 | - | |
| Fish intake frequency (servings per week) | |||||
| <1 | 62.1 | 61.8 | 62.6 | 0.6985 | |
| 1–2 | 20.1 | 20.5 | 19.2 | ||
| ≥2 | 17.8 | 17.7 | 18.1 | ||
| Omega-3 fatty acids (gm/day) | |||||
| (quartile) | 0 (0–0.0155) | 27.0 | 27.7 | 25.6 | |
| 1 (0.0155–0.0410) | 23.8 | 23.5 | 24.3 | 0.1660 | |
| 2 (0.0410–0.1075) | 24.4 | 25.0 | 23.3 | ||
| 3 (0.1075–4.7775) | 24.8 | 23.8 | 26.8 | ||
| Serum selenium (µg/L) a d | 137.2±1.39 | 136.3±1.4 | 138.1±1.6 | 0.1139 | |
a
Weighted mean±standard error
b
Geometric mean (95% confidence limit)
c
Urinary mercury data are available in one-third of the survey population (n=2,201) where urinary creatinine and creatinine-corrected urinary mercury were calculated.
p-value from the Rao-Scott log-likelihood ratio test (continuous variables) or the Rao-Scott Chi-square test (categorical variables)
d
Serum selenium data are only available from the NHANES 2003–2004 survey, including 2,117 participants aged 40 years or older
Hypertension was defined as those individuals who have taken anti-hypertensive medication, have a systolic blood pressure of ≥140 mmHg, or have a diastolic blood pressure of ≥ 90 mmHg