title: Sex difference in urine concentration across differing ages, sodium intake, and level of kidney disease.
abstract: Men are known to be at greater risk of urolithiasis and cardiovascular and renal diseases than women. Previous studies suggest that greater urine concentration is associated with acceleration of progression of chronic kidney disease (CKD), increased urinary albumin excretion, and delayed renal sodium excretion. The present review addresses possible sex-related differences in urine volume and osmolality (U(osm)) that could participate in this male risk predominance. Because of the scarcity of information, we reanalyzed 24-h urine data collected previously by different investigators for other purposes. In nine studies concerning healthy subjects (6 studies) or patients with CKD or diabetes mellitus, U(osm) (or another index of urine concentration based on the urine/plasma creatinine concentration ratio) was 21-39% higher (i.e., about a 150 mosm/kgH2O difference) in men than in women. Urine volume was not statistically different. Thus, the larger osmolar load of men (related to their higher food intake) is excreted in a more concentrated urine with no difference in urine volume. This sex difference was not influenced by the level of sodium excretion and was still present in CKD patients. Sex differences in thirst threshold, AVP level, and other regulatory mediators may all contribute to the higher male U(osm). Because of the previously demonstrated adverse effects of vasopressin and/or high urine concentrating activity, the greater tendency of men to concentrate urine could participate in their greater susceptibility to urolithiasis and hypertension and to the faster progression towards end-stage renal failure.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale Unite 652, 15 rue de l'école de Médecine, 75006 Paris, France.
authors.forename: Julie
authors.initials: J
authors.lastname: Perucca
authors.forename: Nadine
authors.initials: N
authors.lastname: Bouby
authors.forename: Pierre
authors.initials: P
authors.lastname: Valeix
authors.forename: Lise
authors.initials: L
authors.lastname: Bankir
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D005260:Female; D006801:Humans; D007671:Kidney Concentrating Ability / Q000502:physiology*; D007674:Kidney Diseases / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D012727:Sex Characteristics; D012982:Sodium, Dietary / Q000494:pharmacology*
chemical_list: D012982:Sodium, Dietary