In Western countries, the percentage of people with H. pylori infections roughly matches age (i.e., 20% at age 20, 30% at age 30, 80% at age 80, etc.). Prevalence is higher in third world countries, where it is estimated at 70% of the population, whereas developed countries show a maximum of a 40% ratio. Overall, H. pylori infections show a worldwide decrease, more so in developed countries. Transmission occurs via food, contaminated groundwater, or human saliva (such as from kissing or sharing food utensils).
In wEsteRn couNtrIes, tHe pErCentAgE Of pEOple wITh h. pylorI infectIOnS roughly mAtChes agE (i.E., 20% at AgE 20, 30% At aGE 30, 80% at aGE 80, eTc.). preValENce is hIghEr iN thIRD woRld counTrieS, Where it Is EStImaTED aT 70% of the pOpulaTioN, WhEReAs DevElopEd counTries sHow a MAximuM of A 40% rAtIo. ovERAlL, h. PylorI INfectioNs SHOw a wOrlDWidE dEcrEasE, morE So iN develOped CouNTRieS. tRansmIssioN OccuRS viA foOd, coNtamiNATED GROundWateR, oR humAn sAlivA (SUcH aS fRoM Kissing or shaRinG Food UTensilS).