Story highlights 111-year-old New Yorker certified as the oldest man in the world died Sunday

Alexander Imich was a published author with a doctorate in zoology

He fled Poland when the Nazis took over, survived labor camp in Russia before moving to the U.S.

Sakari Momoi, 111, of Japan is now the oldest man in the world

A 111-year-old New Yorker who had been certified as the oldest man in the world has died.

Alexander Imich died Sunday morning at a senior residence in Manhattan, his niece, Karen Bogen, confirmed to CNN.

Imich was certified as the oldest man in the world this April by the Gerontology Research Group of Torrance, California

"He was remarkable," Bogen said.

"He was so independent until very recently, and he just had an incredible curiosity about life."

Photos: People who made it to 100 and beyond Photos: People who made it to 100 and beyond Fauja Singh is recognized as the first 100-year-old to ever run a marathon. The great-grandfather, nicknamed the "Turbaned Tornado ," continues to run or walk every day. Now 106, he took up running to overcome his grief after the death of his wife and a son. He ran his first marathon at age 89. The key to life: "Laughter and happiness. That's your remedy for everything." Hide Caption 1 of 19 Photos: People who made it to 100 and beyond Italian Luigina Vigiconte, 101, offered this advice: "Always be optimistic, never bitter, and always be polite with people." Vigiconte, who has eight sons, lives in Acciaroli, south of Naples, where one in 10 people is a centenarian. Scientists who have studied the area say the Mediterranean diet, genetics, regular exercise and the climate contribute to the longevity of the population. Hide Caption 2 of 19 Photos: People who made it to 100 and beyond Vincenzo Baratta, 103, who also lives in Acciaroli, said there are two secrets to his long life. One is his diet; the farmer eats only once a day and avoids meat. He eats some fish and homemade pasta and has only one glass of wine per day. His other key: having "a lot of women in his life." A neighbor said he has gone through several caregivers because he made so many passes at them. Hide Caption 3 of 19 Photos: People who made it to 100 and beyond Misao Okawa of Osaka, Japan, was 117 when she died April 1, 2015. She was the world's oldest person at the time, according to Guinness World Records. She was born on March 5, 1898, and had three children. Her husband died in 1931. She kept in shape throughout much of her life, saying that helped her live so long; at 102, she said she did leg squats to keep healthy. She didn't start using a wheelchair until she turned 110. Hide Caption 4 of 19 Photos: People who made it to 100 and beyond Ruline Steininger, 103, was one of the first people in Iowa to vote for Hillary Clinton in September . The former schoolteacher, who cast her first vote for Franklin D. Roosevelt in 1936, said that staying politically active kept her young but also told her local paper that the secret to her long life was "I just keep not dying." She eventually did, in February. Hide Caption 5 of 19 Photos: People who made it to 100 and beyond Ruth Frith died February 28 at the age of 104. At 102, the Australian native was the oldest living competitor at the World Masters Games in Sydney, where she won several gold medals and set world records. Her advice for a long life? Avoid smoking, drinking and vegetables. She was also an optimist: "Every year brings something new. I've always been content with what I have." Hide Caption 6 of 19 Photos: People who made it to 100 and beyond Konstantinos Spanos, 103, lives in Ikaria, a Greek island with a reputation for long-lived residents. Sponos said the key to his long life is modesty in everything, including "food, women and entertainment," although he might also want to add reading. He reads five hours a day. Hide Caption 7 of 19 Photos: People who made it to 100 and beyond Mieko Nagaoka, a 100-year-old Japanese woman who became the world's first centenarian to complete a 1,500-meter freestyle swim, hopes to swim until she is 105. She took up swimming at age 80 to help with a knee problem. She credits the exercise with her healthy and long life. She trains four days a week. Hide Caption 8 of 19 Photos: People who made it to 100 and beyond James Sisnett was born February 22, 1900, in Barbados. He made it to 113 and believed he lived that long by eating good food; having a daily "little one," his name for an alcoholic drink; and "God's grace." He worked as a blacksmith, a sugar factory worker and a farmer before retiring at age 70. His longevity made him a local celebrity. His only real health challenge toward the end of his life was hearing loss. He died in May 2013. Hide Caption 9 of 19 Photos: People who made it to 100 and beyond Mississippi Winn was born March 31, 1897, in Benton, Louisiana, and lived to be 113. She maintained her independence until age 103; at 105, she was still walking and working out daily at a local track. Winn said exercise and an optimistic attitude helped her live a long and healthy life. She died in January 2011. Hide Caption 10 of 19 Photos: People who made it to 100 and beyond Man Kaur, 101, is still a competitive runner and javelin thrower. From Chandigarh, India, the great-grandmother didn't start competing in sports until she was 93. She credits her daily training, positivity and her avoidance of fried food for her long life. Hide Caption 11 of 19 Photos: People who made it to 100 and beyond Susannah Mushatt Jones lived to 116. Born in Lowndes County, Alabama, she moved to New York to work as a live-in child care provider. Earning only $50 a week, she put three nieces through college. She attributed her longevity to clean living, not smoking or drinking, and surrounding herself with loving family members and friends. Sleep also helped, she said. Hide Caption 12 of 19 Photos: People who made it to 100 and beyond Jiroemon Kimura was born April 19, 1897, and died June 12, 2013, at the age of 116. The retired Japanese postal worker attributed his long life to eating light, working in the sunshine and not smoking. After his postal career, he worked on a farm: "I am always looking up towards the sky; that is how I am." Of his six siblings, five lived to the age of 90. Hide Caption 13 of 19 Photos: People who made it to 100 and beyond Violet Mosse-Brown, 117, is the current oldest person in the world. She grew up in Jamaica, born 67 years before the country was founded, and said she earned that title by avoiding rum and through her "faith in serving God." The music teacher and church organist still keeps her mind active, keeping the records for the local cemetery. Hide Caption 14 of 19 Photos: People who made it to 100 and beyond Jeanne Calment was born February 21, 1875, and lived to the age of 122 in Arles, France (home of the painter Vincent Van Gogh, whom she met as a little girl). At 85, she took up fencing lessons. At 100, she was still riding her bike. She said she ate more than 2 pounds of chocolate a week and only quit smoking at age 120 -- not for health reasons but because she could not see well enough to light her cigarettes. She credited her longevity to port wine, her sense of humor and a diet rich in olive oil. She died in August 1997. Hide Caption 15 of 19 Photos: People who made it to 100 and beyond Yisrael Kristal, 113, lives in Haifa, Israel, but grew up in Poland and survived being sent to Auschwitz. He ran candy stores in Lodz and in Haifa but keeps a healthy and simple diet. He credited that, along with prayer, for his longevity. He celebrated his bar mitzvah, which had been delayed by World War I, when he turned 113. Hide Caption 16 of 19 Photos: People who made it to 100 and beyond Emma Morano made it to 117. The Italian credited her long life with ending her marriage to an abusive spouse and eating a regular diet of raw eggs and cookies. She loved cookies so much , she hid them under her pillow so no one else would eat them. Hide Caption 17 of 19 Photos: People who made it to 100 and beyond Ann Nixon Cooper became famous after President-elect Barack Obama used her story on election night 2008 to talk about the country's progress. "She was born just a generation past slavery," Obama said. "At a time when women's voices were silenced and their hopes dismissed, she lived to see them stand up and speak out and reach for the ballot." She died in 2009 at age 107. The secret to her long life, she said, was being cheerful: "I've always been a happy person, a giggling person, a wide-mouthed person." She also kept fit, dancing the electric slide until age 103. Hide Caption 18 of 19 Photos: People who made it to 100 and beyond Edward Rondthaler was born June 9, 1905, in Bethlehem, Pennsylvania, and he died in 2009 at the age of 104. He was a noted typographer, earning a national reputation for helping to usher in the age of photographic typesetting, according to The New York Times . Photographic typesetting was an easier way to print than hot-metal type. Rondthaler credited cold showers for his longevity. He died at his home in Cedar City, Utah. Hide Caption 19 of 19

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Imich was born in Poland on February 4, 1903, according to a longtime friend in New York, Michael Mannion.

He and his wife, Wela, fled Poland when the Nazis took over, survived a labor camp in Russia and in 1951 moved to the United States, Mannion said.

His wife, who was a prolific artist and therapist in New York, died in 1986, according to Bogen.

"His apartment was filled with her artwork," she said.

They had no children.

Mannion told CNN that when Imich learned he was the oldest man in the world, he "enjoyed the attention."

"It was his work that he was most proud of, and he was happiest when the attention included his scientific work," Mannion said.

Despite a doctorate in zoology, Imich's passion was investigating paranormal activity, Mannion said. He detailed his encounters with the supernatural in "Incredible Tales of the Paranormal," a journal that was published when he was 92.

While Imich's lengthy life can be attributed to diet, exercise and nutrition, Mannion says his great passion and curiosity for life were the real keys to his longevity.

"He had such an ability to turn adversity into something positive. That intense curiosity was there until the last days," said Mannion, who had visited Imich the night before he died.

A 116-year-old Japanese woman, Misao Okawa, is the world's oldest living person, according to the Gerontology Research Group. The title of world's oldest man now goes to Sakari Momoi, also of Japan, who was born just a day after Imich in 1903, the group said.