TABLE 1.

Characteristics of the case-control studies included in the systematic review and meta-analysis of the relation between dairy product intake and bladder cancer in the adult population¹

Reference	Country	Study/period of data collection (y)	Age distribution (y)	Sample size	Dietary assessment	Dairy products	Dairy amount comparison	Number of bladder cancer events	Variables of adjustment	Risk of bias2
Mettlin and Graham (15)	United States	1957–1965	NA	1594	Interview	Milk	Servings per day (5 categories)	569	Age	Low
Risch et al. (16)	Canada	1979–1982	35–79	1618	Questionnaire	Milk	Servings per day (2 categories)	826	Age, sex, area of residence, lifetime smoking consumption, and history of diabetes	High
Slattery et al. (17)	United States	1977–1982	21–84	1308	Interview	Milk	Servings per week (4 categories)	419	Age, sex, smoking status, diabetes, and bladder infection	High
Mettlin et al. (18)	United States	1982–1990	18–97	1478	Questionnaire	High-fat milk 2% fat milk Low-fat milk	Servings per day (3 categories)	178	Age, sex, smoking history, education, and county of residence	Low
Riboli et al. (19)	Spain	1985–1986	<80	1224	Dietary questionnaire	Dairy Butter/cream	Quartiles of intake	432	Age, sex, smoking, area of residence, total calories	Moderate
Wilkens et al. (20)	United States	1977–1986	30–93	783	FFQ/32 items	Milk	Tertiles of intake	261	Age, smoking status, pack-years, employment in a high-risk occupation, consumption of dark green vegetables in men, and total vitamin C consumption in women	High
Lu et al. (21)	Taiwan	1996–1997	67.5	200	FFQ	Milk	Nonintake vs. intake	40	Age, sex, date of admission, family history, ethnicity, and smoking status	Moderate
Wakai et al. (22)	Japan	1996–1999	20–99	592	FFQ/97 items	Dairy	Quartiles of intake	297	Age, sex, smoking, and occupational history as a cook	Low
Balbi et al. (23)	Uruguay	1998–1999	40–89	720	FFQ/64 items	Dairy Cheese Butter High-fat milk	Tertiles of intake	144	Age, BMI, calories	Moderate
Ohashi et al. (24)	Japan	1997–1998	49–80	625	Questionnaire	Fermented dairy Yakult	Servings per day (3 categories)	180	Age, sex, and smoking	Low
Radosavljević et al. (25)	Serbia	1997–1999	26–81	260	FFQ	High-fat milk Low-fat milk Yogurt	Nonintake vs. intake	130	Age, sex, smoking, place of residence	Low
Wakai et al. (26)	Japan	1994–2000	20–79	744	FFQ	Milk	Quartiles of intake	124	Age, sex, cumulative consumption of cigarettes, year of first visit	Low
Jiang et al. (27)	United States	1987–1999	25–64	3172	Interview	Milk	Quartiles of intake	1586	Age, sex, race, level of education, use of nonsteroidal anti-inflammatory drugs, carotenoid intake, number of years as hairdresser/barber, cigarette smoking status, duration of smoking, and intensity of smoking	Low
La Vecchia et al. (28)	Italy	1985–1987	45–74	344	FFQ	Milk Cheese Butter	Tertiles of intake	163	Age and sex	Moderate
Hemelt et al. (29)	China	2005–2008	65	824	Interview	Milk	Nonintake vs: - Intake - < Daily or daily - 1 cup or >1 cup	432	Age, sex, smoking status, smoking frequency, and smoking duration–adjusted ORs	Low
Brinkman et al. (30)	Belgium	1999–2004	50–80	575	Validated FFQ/322 items	Milk Cheese	Tertiles of intake	198	Sex, age, smoking status, number of cigarettes smoked per day, number of years smoking, occupational exposure to polycyclic aromatic hydrocarbons or aromatic amines, and energy intake	Low
Isa et al. (31)	China	2005–2008	40–80	956	FFQ/35 items	Dairy	Servings per week (5 categories)	487	Sex, age, smoking status, smoking duration, smoking amount, and other food groups	Low
Ronco et al. (32)	Uruguay	1996–2004	30–89	1735	FFQ/64 items	Milk Butter Cheese	Tertiles of intake	225	Age, residence, education, BMI, smoking, alcohol drinking, meat consumption, total energy, and total vegetable and fruit intakes	Low

¹NA, not available; PAH, polycyclic aromatic hydrocarbon.

²Risk of bias assessed using the Quality in Prognosis Studies (QUIPS) tool.