Table 2.

Risk factors associated with kidney stone formations.

Number	Risk factors	References
1	Lifestyle habits and dietary/nutritional factors: such as excessive intake of animal proteins and salt and deficiencies of chelating agents like citrate, fiber, and alkali foods	[9, 13, 19, 45]
2	Metabolic disorders: such as hypercalciuria, hypocitraturia, hyperoxaluria, hyperuricosuria, and history of gout (defective metabolism of uric acid)	[38, 46–48]
3	Hypercalcemic disorders: primary hyperparathyroidism and other disturbances of calcium metabolism	[49]
4	Urine composition: excessive excretion of promoters of urinary crystallization and reduced excretion of inhibitors (urine deficient in inhibitory substances)	[1, 45, 49]
5	Low urine volume: inadequate water intake (dehydration and supersaturated urine)	[45, 49, 50]
6	Recurrent urinary tract infections: abnormalities of urinary pH and alkalinization of urine by bacterial urease (such as Proteus mirabilis)	[38, 49]
7	Genetic predisposition/inherited disorders: family history of stones (genetic susceptibility); genetic monogenic diseases (single abnormal gene disorders on the autosomes); renal tubular acidosis	[1, 9, 48, 49, 51]
8	Anatomical abnormalities: factors such as defects in medullary sponge kidney, ureteropelvic junction stenosis, pyeloureteral duplication, polycystic renal disease, and horseshoe kidney	[1, 48, 49, 52]
9	Hypertension	[46]
10	Obesity	[46–48]
11	Climate change (global warming), occupation, geographic conditions, and seasonal variations (higher in summer than winter)	[1, 49]
12	Inflammatory bowel disease and other intestinal malabsorption or associated disease states	[9, 49]
13	Absence of intestinal oxalate-degrading bacteria	[53, 54]
14	Lithogenic drugs: such as indinavir (Crixivan), a protease inhibitor, sulfonamides (sulfadiazine), uricosuric agents, which have low solubility andpromotes the formation of calculi, and ceftriaxone (high dose on long terms)	[28, 38, 49, 50]