UPDATE 2-Brazil's Nubank posts higher-than-expected adjusted profit in first quarter

(Adds more details in paragraphs 6-8 and analysts remarks in paragraphs 9-10)

SAO PAULO, May 14 (Reuters) - Brazilian digital lender Nubank's adjusted net profit more than doubled in the fist quarter when compared to the year-earlier period, surpassing analysts estimates, as growth in its credit loan portfolio boosted revenues.

Nubank's adjusted net profit surged 143% to $442.7 million from the year earlier, while analysts polled by LSEG expected a $404.8 million adjusted profit. Profit was up despite rising loans overdue rates raised some concerns.

Its return on equity (ROE) - a measure of financial performance - came in at 23%, stable from the fourth quarter, but up from 11% a year ago.

Earlier this month, Nubank said it has exceeded 100 million customers in Latin America, making it the first digital banking platform outside Asia to do so.

More than 90 million of these customers are in Brazil, while the digital lender has also been growing in Mexico and, more recently, in Colombia.

The lender's revenue rose 69% in the quarter to $2.74 billion, above analysts estimates of $2.49 billion. Net interest income almost doubled year-on-year, with Nubank attributing the performance to the grow of personal loan and credit cards portfolio.

However, the lender's loans overdue by 15 to 90 days in Brazil increased 0.6 percentage points in 12 months to 5%. Loans overdue by more than 90 days were at 6.3% from 5.5%. They both also rose from the fourth quarter.

Nubank said its short-term delinquency rates were impacted by seasonal effects, while longer rates followed "the expected stacking behavior of the early delinquency buckets in previous periods".

"Nubank presented another quarter of earnings growth, combined with positive business expansion trends", Santander analyst Henrique Navarro wrote in a report, while raising concerns on assets quality.

"Asset quality was a lowlight, in our view, and this might raise some concerns regarding credit quality deterioration in upcoming quarters", Navarro said. (Reporting by Andre Romani and Patricia Vilas Boas in Sao Paulo Editing by Valentine Hilaire, Matthew Lewis and Lincoln Feast.)