| Abstract | Objectives: The aim of this study was to evaluate the available RCTs and systematic reviews
regarding the efficacy and safety of antioxidant vitamin supplementation in preventing and
slowing the progression of age-related cataract and to examine if we could find enough evidence
for this.
Materials and methods: The Cochrane systematic review “Antioxidant vitamin
supplementation for preventing and slowing the progression of age-related cataract” was used
as a base and according to its inclusion criteria we tried to find RCTs and systematic reviews
published after it, yielding additional proof of the safety and efficacy of antioxidant vitamin
supplementation regarding age-related cataracts. We searched PubMed, CENTRAL and
DARE. After the search, we made a quality assessment of the systematic review using RAMSTAR.
Results: The Cochrane systematic review involved nine trials, with 117,272 participants overall
and an age range of ≥ 35 years. The trial follow-up ranged from 2.1 to 12 years and the trials
were conducted in Italy, Finland, the United Kingdom, Australia, India and the United States.
The antioxidant vitamins were dosed above the recommended daily allowance. No evidence
was found supporting that antioxidant vitamin supplementation could reduce the risk of
progression of cataract, cataract development, cataract extraction or that it could slow the loss
of visual acuity. No evidence of effect of supplementation of beta-carotene in reducing the risk
of cataract could be found in the pooled analysis (RR 0.99, 95%, CI 0.91-1.08; number of
participants: 57,703) nor could be evidence found for a reduction of the risk of cataract
extraction (RR 1.00, 95% CI 0.91-1.10; number of participants: 86,836). For the
supplementation with vitamin E no risk reduction in cataract incidence could be found in the
pooled analysis either (RR 0.97, 95% CI 0.91-1.04; number of participants: 50,059) or of
cataract extraction (RR 0.98, 95% CI 0.91 - 1.05; number of participants: 83,956). 7.4 - 15.8%
of patients on beta-carotene developed hypercarotenodermia (yellowing of skin). Only one
additional RCT was found involving 11,267 exclusively male participants from the United
States, Canada and Puerto Rico, with an age range of 50 years and older. Only part of this RCT
was of interest for us, the part concerning supplementation with vitamin E. It lasted 5.6 years.
Conclusion: Not enough evidence could be found to prove the safety and efficacy of
supplementation with antioxidant vitamins for the slowing and the prevention of age-related
cataract. Further research among non-well-nourished populations or well-nourished
populations but regarding antioxidant blood levels rather than supplementation could be
conducted in the future. |
| Abstract (croatian) | Ciljevi: Cilj ove studije bio je procijeniti dostupne RCT-ove i sustavne preglede koji se odnose
na učinkovitost i sigurnost suplementacije vitamina antioksidansa u prevenciji i usporavanju
napredovanja katarakte povezane sa starenjem te ispitati možemo li pronaći dovoljno dokaza
za to.
Materijali i metode: Cochraneov sustavni pregled „Dopuna antioksidativnim vitaminima za
prevenciju i usporavanje napredovanja katarakte povezane sa starenjem” korišten je kao osnova
i prema njegovim kriterijima za uključivanje pokušali smo pronaći RCT-ove i sustavne preglede
objavljene nakon Cochranovom sustavnom pregledu, koji su dali dodatne dokaze o sigurnost i
učinkovitosti antioksidativnih vitaminskih suplementacija u pogledu katarakte povezane sa
starenjem. Pretražili smo PubMed, CENTRAL i DARE. Nakon pretrage napravili smo procjenu
kvalitete sistematskog pregleda pomoću R-AMSTAR-a.
Rezultati: Cochrane sustavni pregled uključivao je devet ispitivanja s ukupno 117 272 osobe
u dobi od 35 godina i više. Praćenje ispitivanja kretalo se od 2,1 do 12 godina, a ispitivanja su
provedena u Australiji, Finskoj, Indiji, Italiji, Ujedinjenom Kraljevstvu i Sjedinjenim
Državama. Doze antioksidativnih vitamina premašile su preporučenu dnevnu dozu. Nije bilo
dokaza o učinku dodataka vitamina antioksidansa u smanjenju rizika od katarakte, ekstrakcije
katarakte, progresije katarakte ili usporavanja gubitka vidne oštrine. U zbirnim analizama nije
bilo dokaza o učinku suplementacije beta-karotena u smanjenju rizika od katarakte (dva
ispitivanja) (relativni rizik 0,99, 95% interval pouzdanosti 0,91-1,08; broj ispitanika 57 703) ili
u smanjenju rizika od ekstrakcije katarakte (tri ispitivanja). Udio sudionika koji su razvili
hiperkarotenodermiju (žutilo kože) dok su uzimali beta-karoten kretao se od 7,4% do 15,8%.
Pronađen je samo jedan dodatni RCT koji je uključivao 11.267 isključivo muških sudionika iz
Sjedinjenih Država, Kanade i Portorika, s dobnim rasponom od 50 godina i više. Zanimao nas
je samo dio ovog RCT-a, dio koji se odnosi na suplementaciju vitaminom E. Trajao je 5,6
godina.
Zaključak: Ne može se pronaći dovoljno dokaza za sigurnost i učinkovitost antioksidativnih
vitaminskih suplemenata za prevenciju i usporavanje katarakte povezane sa starenjem. U
budućnosti bi se mogla provesti daljnja istraživanja među neuhranjenim ili dobro uhranjenim
stanovništvom, ali u vezi s razinama antioksidansa u krvi, a ne suplementaciji. |
