Table 1.

Approach Used to Assess Longitudinal and Acute Associations Between Intake of Beverage Types and LUTS in Analysis of the Boston Area Community Health Survey, 2002–2010

Association Examined	Longitudinal (After ∼5 Years)	Acute (Cross-Sectional)	Intake Changes (Longitudinal)a
Study time points (years) used	Baseline (2002–2005) and follow-up (2006–2010)	Follow-up (2006–2010)	Baseline (2002–2005) and follow-up (2006–2010)
Beverage intake assessment	Baseline	Follow-up	Change from baseline to follow-up
Time reference	Usual beverage intake over the previous year	Average daily intake in previous 7 days	Average daily intake in previous 7 days
Measurement tool	Self-administered validated food frequency questionnaireb (46, 47)	In-person interview	In-person interview
Question format	“How many glasses of these beverages do you drink per day or per week?”	“Think about the past 7 days. How many servings of [item] did you drink each day? A serving is one 8 oz. glass or cup.”	“Think about the past 7 days. How many servings of [item] did you drink each day? A serving is one 8 oz. glass or cup.”
Response format	Categorical responses to “How often” (ranging from “never or less than once per month” to “2+ per day”) and “How much,” (ranging from 1 to ≥5, with a serving size of glass used for juice, bottles or cans for soda, and cup for tea/coffee)	Open numeric field	Open numeric field
Operationalized measure	Servings per day
LUTS assessment	Baseline and follow-up	Follow-up	Baseline and follow-up
Measurement tools	○ IPSS (20, 22, 23) ○ Urgency assessment included the relevant IPSS item (difficulty postponing urination) and additional questions on having had a strong urge or pressure to urinate immediately, with little or no warning, at least several times in the past week (48)
Operationalized measures	Progression of LUTS from baseline to follow-up (yes/no), defined as IPSS increase of:	Continuous IPSS at follow-up for:	Progression of LUTS from baseline to follow-up (yes/no), defined as IPSS increase of:
	≥3 points for total score (44) ≥2 points for voiding subscore ≥2 points for storage (daytime frequency, urgency, or both) subscore ≥2 points for urgency symptoms	Total score Voiding subscore Storage (daytime frequency, urgency, or both) subscore Urgency present at follow-up (yes/no)	≥3 points for total score (44) ≥2 points for voiding subscore ≥2 points for storage (daytime frequency, urgency, or both) subscore ≥2 points for urgency symptoms
Exclusions from analysis	Did not complete the baseline food frequency questionnaire Not eligible for progression because of severely high baseline symptom score (e.g., for LUTS, IPSS ≥33)	None	Not eligible for progression because of severely high baseline symptom score (e.g., for LUTS, IPSS ≥33)
Sample sizes available for analysis
Men	1,101	1,610	1,608
Women	1,727	2,534	2,532

Abbreviations: IPSS, International Prostate Symptom Score; LUTS, lower urinary tract symptoms.

^a Analyses were conducted as secondary analyses only for total coffee and total soda, because the questions for other or more specific beverage types were not available or comparable between baseline and follow-up, in either the in-person interview or the food frequency questionnaire.

^b In addition to usual beverage intake, the baseline food frequency questionnaire was used to derive total caffeine intake from chocolate, coffee, green/black/iced tea, and cola.