Primary Independent Variables
For descriptive purposes only, we created specific medication variables to indicate new use
(year three only), continuing use (years two and three) and past use (years one and/or two
only). The primary independent variables were current use (combination of new use and
continuing use) versus no use of specific medications at year 3 derived from the above
mentioned computerized files of participants’ coded prescription medication data. The
selection of specific medication classes was based on those previously reported to be
potentially associated with urinary incontinence.4 One class we examined was the use of
alpha blockers (i.e., prazosin, doxazosin, terazosin). No women reported the use of two other
alpha blockers; alfuzosin or tamsulosin. Other classes we examined were diuretics (i.e.,thiazide, loop and potassium sparing) and estrogen (oral, vaginal and transdermal dosage
forms). We also examined the combined use of central nervous system drugs. Consistent
with previous work from our group, opioid receptor agonist analgesics, antidepressants,
antipsychotics and benzodiazepine receptor agonists comprised CNS medications.16 Also
consistent with previous work from our group, we examined anticholinergic medication use
(defined as those agents with established muscarinic receptor blockage in vitro that were not
included in the CNS medications variable as described above or bladder antispasmodics that
also appear on a commonly accepted list of medications to be avoided in the elderly).17