* FTSEurofirst 300 index tumbles over 3 percent
* Deutsche Bank top faller among big banks
* Energy shares track weaker oil prices
* Greek stocks sink to lowest in over 25 years (Adds details, updates prices)
By Danilo Masoni and Atul Prakash
MILAN/LONDON, Feb 8 (Reuters) - European shares touched a 16-month low on Monday with investors rattled over a slowdown in global economic growth and newly concerned about the region's banking sector.
The pan-European FTSEurofirst 300 index was down 3.1 percent at 1,243.21 points by 1521 GMT, its lowest level since October 2014.
The STOXX Europe 600 banking index, down 4.7 percent, was among the top decliners. The index is down more than 22 percent so far this year on concerns about banks' profitability and capital strength in an environment where monetary stimulus continues to put pressure on margins.
The cost of insuring the European financial sector's senior debt against default also climbed to its highest level since late 2013.
Shares in Deutsche Bank fell 6.5 percent, leading decliners on Europe's Stoxx 50 index. Elsewhere in the sector, BNP Paribas, ING Santander and Barclays were all down by more than 4 percent.
"Investors are starting to think that banks are not as solid as previously thought," said Giuseppe Sersale, fund manager at Italy's Anthilia Capital. He added the negative sentiment was compounded by signs of a U.S. economic slowdown, persistent worries about China, and continued volatility in oil prices.
Jaisal Pastakia, investment manager at Heartwood Investment Management, said there were mounting concerns that banks' profitability will be squeezed by negative interest rates and prolonged dovish monetary policy.
"Weak investor sentiment has been accentuated by the Bank of Japan's decision to apply negative interest rates on excess reserves, which follows moves already taken by the European Central Bank, Sweden and Denmark. A high level of unprofitable loans on banks' balance sheets impacts the broader economy by stifling both domestic demand and bank lending growth."
Earlier this month, Credit Suisse reported its first full-year loss since 2008 after booking a big impairment charge at its investment banking business, while Deutsche Bank posted a record loss for 2015.
The Athens stock index fell 7.9 percent to hit its lowest level since at least 1991. Traders and analysts said the fall was due to uncertainty that a bailout review by the country's lenders could drag on.
Energy stocks also lost ground, with the European oil and gas index felling 3.5 percent after crude oil prices slipped again after earlier gains.
Other European sectors sensitive to macroeconomic activities, such as autos, media, construction and technology, all fell by more than 3 percent.
"It's a difficult market environment. I would have hoped for a rebound in the market but after the last week's actions, this is certainly off the table. The economic newsflow has to improve. So far it hasn't on a decisive scale," Gerhard Schwarz, head of equity strategy at Baader Bank in Munich, said.
European and U.S. shares fell sharply on Friday after U.S. jobs data showed employment gains slowed more than expected in January. Some recent economic numbers from China, the world's second biggest economy, have also disappointed. (Additional reporting by Danilo Masoni in Milan; Editing by Mark Heinrich)