NodeJS export variable

Im writing a nodejs module and I need to pass variable data from the main file to the functions, im doing this:

var region;
var api_key;

exports.region = region;
exports.api_key = api_key;


module.exports = {

 getSummonerId:  function(sum, callback) {

   var summoners = {};
   var summoner = sum.replace(/\s+/g, '');

   request("http://ift.tt/1zY3bLg"+region+"/v1.4/summoner/by-name/"+summoner+"?api_key="+api_key, function(error, response, body) {
         summoners[summoner] = JSON.parse(body);
         callback(summoners[summoner][summoner].id);
   });
 }
}

And in the main file:

var lol = require('./apiwrapper.js');

lol.api_key = "example";
lol.region  = "las";


lol.getChampions(function(data) {
   console.log(data);
})

But from apiwrapper.js those two variables value is always "undefined".

Can some point me in the right direction?

Thanks in advance.