Table 6.

Dietary supplement use (non-multivitamin supplements and multivitamins + individual supplements) and all-cause mortality stratified by dietary nutrient intake

Each individual supplementMultivitaminsd + each individual supplement
NonusersUsersNonusersUsers
Deaths/nDeaths/nHR (95% CI)cPinteractionDeaths/nDeaths/nHR (95% CI)cPinteraction
Dietary vitamin Aa
 <2,300 IU/d14/240/1N/AN/A8/130/1N/AN/A
 ≥2,300 IU/d522/1,87534/1101.19 (0.84–1.69)193/65024/811.20 (0.78–1.85)
Dietary folatea
 <400 μg/d339/1,20742/901.35 (0.94–1.94)0.12128/43531/671.39 (0.90–2.16)0.20
 ≥400 μg/d217/77510/460.76 (0.39–1.50)81/2519/380.82 (0.39–1.73)
Dietary vitamin Db
 <400 IU/d473/1,60461/2140.85 (0.64–1.13)0.68176/55340/1400.94 (0.65–1.36)0.86
 ≥400 IU/d65/2599/410.70 (0.32–1.55)22/787/270.76 (0.28–2.10)
Dietary vitamin Eb
 <11.25 IU/d240/803104/3921.00 (0.79–1.27)0.2796/32180/2881.15 (0.84–1.57)0.02
 ≥11.25 IU/d162/55360/2650.80 (0.58–1.11)75/21640/2040.61 (0.39–0.94)
Dietary irona
 <8 mg/d54/17911/281.40 (0.65–3.03)0.8828/767/171.48 (0.58–3.79)0.79
 ≥8 mg/d427/1,60177/1831.37 (1.06–1.77)153/53449/1211.42 (1.01–2.01)
Dietary calciuma
 <1,200 mg/d195/631285/1,0160.93 (0.77–1.13)0.48103/317202/7420.93 (0.72–1.20)0.92
 ≥1,200 mg/d48/16051/2390.76 (0.48–1.20)24/7341/1830.85 (0.47–1.53)
  • aCancer survivors were categorized into two groups depending on whether their nutrient intake from a diet was < or ≥ RDA.

  • bCancer survivors were categorized into two groups depending on whether their nutrient intake from a diet was < or ≥ half the RDA.

  • cHRs and 95% CIs compared with nonusers of dietary supplement (overall or multivitamin) in each stratified category as a reference group. Adjusted for age, energy intake, body mass index, physical activity level, current smoking, total comorbidity index, perceived general health, history of diabetes, history of high blood pressure, cancer type, cancer stage, surgery, chemotherapy, number of cancers, current cancer treatment, years since cancer diagnosis, and diet quality score.

  • dMultivitamins for the elderly are purposely iron-free because individuals aged 50 and older require less iron and generally meet their iron needs through diet alone, and high iron stores have been suggested to have adverse health effects.