Table 2.

Selected participant characteristics at baseline across quintiles of the mineral scorea; Iowa Women's Health Study, 1986–2012

Mineral score quintiles
Characteristicsb1 (≤ 15) median = 12 (N = 5,369)2 (1516) median = 15 (N = 6,464)3 (1718) median = 17 (N = 7,637)4 (1920) median = 18 (N = 7,287)5 (2130) median = 21 (N = 8,464)
Age (years)61.7 (4.3)61.5 (4.1)61.5 (4.2)61.5 (4.2)61.5 (4.2)
Education < college graduate (%)13.516.318.818.919.7
Family history of colorectal cancerc (%)2.53.33.03.43.1
Diabetes at baseline (%)0.81.11.21.31.5
Hormone replacement therapy (%)
Never67.864.661.359.656.1
Former8.59.711.112.114.3
Current23.725.727.628.329.7
Height (cm)159.9 (6.4)160.1 (6.2)160.2 (6.2)160.5 (6.2)160.7 (6.19)
BMI category (%)
<25 kg/m236.939.541.442.748
25–30 kg/m237.536.836.937.836.3
≥30 kg/m225.623.621.719.515.7
Waist–hip ratio0.852 (0.092)0.844 (0.084)0.841 (0.081)0.834 (0.082)0.833 (0.093)
Physical activity (%)
Low57.554.948.943.737.7
Medium25.326.127.728.429.0
High17.319.023.427.933.4
Smoking status (%)
Never68.263.167.065.161.8
Former15.416.518.020.824.4
Current16.416.215.114.113.8
Alcohol intake (%)
None59.656.354.754.551.8
>0–<15 g/day34.236.338.639.541.9
≥15 g/day6.27.46.76.06.4
Total energy intake (kcal/day)2,093 (938)1,968 (735)1,859 (697)1,728 (650)1,546 (503)
Total fat intake (% kcal/day)50.6 (19.2)59.1 (21.3)65.3 (23.1)74.5 (27.5)86.0 (43.2)
Dietary fiber intake (g/1,000 kcal/day)5.0 (2.6)5.1 (2.5)5.5 (2.8)5.7 (3.4)5.6 (2.6)
Take multivitamin (%)9.3 (8.3)11.4 (9.9)35.6 (14.2)41.3 (12.5)52.4 (17.3)
Take calcium supplement (%)30.3 (25.1)36.2 (23.7)37.9 (27.2)35.4 (12.9)34.3 (10.7)
Total fruits and vegetables intake (servings/wk.)39.1 (22.3)41.1 (21.1)44.8 (25.7)47.7 (32.5)47.5 (24. 6)
Total red and processed meats intake (servings/wk)8.7 (7.2)8.1 (5.3)7.1 (5.0)6.0 (4.1)4.8 (3.1)
Dietary OBSd−0.78 (0.20)−0.73 (0.11)−0.69 (0.13)−0.67 (0.22)−0.58 (0.11)
  • aMineral score calculated from food and supplemental intakes of calcium, magnesium, manganese, zinc, selenium, potassium, iodine, iron, copper, phosphorus, and sodium as described in the text.

  • bAll variables measured at baseline (1986) and are presented as mean (SD) except as otherwise specified.

  • cIn a first-degree relative.

  • dOxidative balance score; a composite of 11 anti- and prooxidant dietary exposures (see text); a higher score represents higher antioxidant relative to prooxidant dietary exposures; study population range: −0.97 to −0.48.