Pregnancy is not a risk factor for gallstone disease: Results of a randomly selected population sample

Table 4 Relative risk for gall bladder stones in relation to selection of study population

Place/region	Populationselection	n	Sex distributionmale:female
Chiayi[23]	Random sample	923	1:1.0
Rome[32]	Factory	2 325	1:1.1
Bergen[40]	Random sample	1 371	1:1.1
Ulm[19]	Blood donors	1 116	1:1.1
Copenhagen[44]	Random sample	4 807	1:1.4
Chiang Mai[38]	Random sample	6 146	1:1.5
Schwedt[41]	Factory	1 616	1:1.6
Okinawa[17]	Inhabitants of an island	2 584	1:1.7
Jiaotong[14]	Random sample	15 856	1:2.0
M.I.C.O.L[24]	Random sample	29 739	1:2.0
Römerstein[20]	Total survey	2 498	1:2.1
Sirmione[21]	Total survey	1 911	1:2.2
Cianciano[22]	Total survey	1 804	1:2.3
Leutkirch	Random sample	2 401	1:2.3