The 2002 Field Representative's Manual defines "high dose or megavitamin therapy" as:

This definition was not routinely shared with respondents.

These include:

• Specific vitamins taken in high dose (VITYCOEN, VITYDHE, VITYVITAD, VITYVITB, VITYZINC, VITACALC, VITAMULTV, VITASELN, VITAMINC, VITAMINE)

• Whether used megavitamin therapy for specific health problem (VITYTREAT)

• Importance of use of megavitamin therapy (VITYIMPORT)

• Reasons for using megavitamin therapy (VITYCOMBIN, VITYHCREC, VITYINTER, VITYMEDCOST, VITYMEDFAIL)

• Whether seeing a practitioner for megavitamin therapy (VITPRAC, VITPRACYR)

• Whether informed conventional medical practitioners of use of megavitamin therapy (VITYLCONVHP, VITYLDENT, VITLDO, VITYLMD, VITYLNURS, VITLPHARM, VITLPSYCHI, VITLPSYCHO)

See VITYTREAT for more detail and the full list of conditions that persons could indicate were treated with megavitamin therapy. Analysts interested in the conditions that megavitamin therapy was used to treat may also wish to consult the following variables:

• First condition for which megavitamin therapy was used (VITYCON1

• Degree of help from megavitamin therapy, 1st condition (VITYCON1HELP)

• Second condition for which megavitamin therapy was used (VITYCON2)

• Degree of help from megavitamin therapy, 2nd condition (VITYCON2HELP)

• Third condition for which megavitamin therapy was used (VITYCON3)

• Degree of help from megavitamin therapy, 3rd condition (VITYCON3HELP)

• Condition count for megavitamin therapy (VITYCONNO)

Many other variables dealing with vitamin use were included in other years of the NHIS. VITYR and its follow-up variables deal with vitamins taken in high dose, but the vitamin variables from other years (1992, 2000, 2005, and 2007) do not specify any particular dosage. For more information about the full range of vitamin variables from years other than 2002, see VITMO and VITANY.