Soo koob maqaalka:  Waligaa ma is waydiisay sababta uu gadhku u noqdo mid cawlan? ama sababta uu gadhka ragga u noqdo mid casaan ah? Ama sababta ay timaha dahabka ah ee cunuggu u baaba'aan kahor inta uusan gaarin 10 sano? Halkan, khabiir ku xeel dheer, Rodney Sinclair, oo ah borofisar ku takhasusay cudurada maqaarka ee Isbitaalka Epworth iyo Jaamacadda Melbourne, wuxuu sharaxayaa sayniska midabka timaha - iyo sababta qaarkeenu ay ugu habaaranyihiin cawl ka badan kuwa kale... Maxaa go'aamiya midabka timaha? Midabka timaha waxaa soo saara unugyada loo yaqaano melanocytes, kuwaasoo u guuraan timaha timaha marka ay timaha timaha u soo baxaan uurka. Unugyada melanositka waxay soo saaraan midabada oo ku biira timaha koraya si ay u soo saaraan timaha midabada dabiiciga ah ee kala duwan. Midabka timaha wuxuu ku xiran yahay joogitaanka iyo saamiga laba kooxood oo melanins ah: eumelanins (midabada bunni iyo madow) iyo pheomelanins (midabada casaan iyo jaalle ah). Inkastoo kala duwanaanshaha saamiga midabadaas ay soo saari karaan midabyo iyo midabyo badan, walaalaha inta badan waxay leeyihiin midab timo oo isku mid ah. Waxaa muuqata in arrimaha hidda-wadaha ay muhiim u yihiin go'aaminta goorta ay timaheenu cawl noqdaan, halkii ay ka ahaan lahaayeen hab-nololeedka, sida uu sheegay Professor Sinclair. Badankeenuba waxaan helnaa 'Grey-yada' ugu horeeya marka aan gaarno da'da 30-ka, sida caadiga ah xidigaha, ka dibna, madaxa oo dhan. Sida ay timaha midabkoodu u kala duwanaan karaan sida ay jidhku u kala duwan yihiin. Tusaale ahaan, ciridka indhaha ayaa ah kuwa ugu madow sababtoo ah waxay ka kooban yihiin eumalanin fara badan. Timaha madaxa caadi ahaan way ka khafiifsan yihiin timaha jilicsan, kuwaas oo inta badan leh midab casaan ah, sababtuna tahay jiritaanka midabada phaeomelanin. Sidoo kale casaanka waxaa badanaa laga helaa timaha gacmaha hoostooda iyo gadhka, xitaa dadka timaha madaxooda ay yihiin kuwo bunni ah. Hormoonnada sida hormoonnada melanocyte-ka kiciya waxay madow keeni karaan timaha khafiifka ah, sida ay u madow keeni karaan heerarka sare ee estrogenka iyo progesterone-ka, oo la soo saaro uurka. Daawooyinka qaarkood, sida kuwa looga hortago duumada, waxay timaha ka dhigi karaan kuwo cad, halka daawooyinka suuxdinta qaarkood ay madow ka dhigi karaan. Maxay caruurta buluuga ahi inta badan u noqdaan kuwo madow? Carruurta madaxa madawga ahi waxay u muuqdaan inay timahoodu madow noqdaan markay da'doodu tahay todobo sano...
Rodney Sinclair waa Professor of Dermatology ee jaamacada Melbourne. Waxay sheegtay in marka aan gaarnay da'da 50 jir, kala badhkeenu ay lumiyeen midabkii timaheena boqolkiiba 50 Waxaa laga yaabaa in cawlka oo si xawli ah u dillaaca uu calaamad u yahay dhiig yari ama xanuun qanjirka 'Thyroid'. Timaha madaxa caadi ahaan way ka khafiifsan yihiin timaha madaxa, kuwaas oo inta badan leh midab casaan ah.