Question: Why star of The Belle of New York Dies in August of 1981?

full_context: Document 1: New Faces of 1952: New Faces of 1952 is a musical revue with songs and comedy skits. It ran on Broadway for nearly a year in 1952 and was then made into a motion picture in 1954. It helped jump start the careers of several young performers including Paul Lynde, Alice Ghostley, Eartha Kitt, Robert Clary, Carol Lawrence, Ronny Graham, performer/writer Mel Brooks (as Melvin Brooks), and lyricist Sheldon Harnick.
Document 2: Ginger Rogers: Ginger Rogers (born Virginia Katherine McMath; July 16, 1911 – April 25, 1995) was an American actress, dancer, and singer, widely known for performing in films and RKO's musical films, partnered with Fred Astaire. She appeared on stage, as well as on radio and television, throughout much of the 20th century.
Document 3: Gwen Verdon: Gwyneth Evelyn “Gwen” Verdon (January 13, 1925 – October 18, 2000) was an American actress and dancer. She won four Tony awards for her musical comedy performances and served as uncredited choreographers assistant and specialty dance coach for both theater and film. With flaming red hair and a quaver in her voice, Verdon was a critically acclaimed performer on Broadway in the 1950s, 1960s, and 1970's. Having originated many roles in musicals she is also strongly identified with her second husband, director–choreographer Bob Fosse, remembered as the dancer–collaborator–muse for whom he choreographed much of his work and as the guardian of his legacy after his death.
Document 4: Cyd Charisse: Cyd Charisse (born Tula Ellice Finklea; March 8, 1922 – June 17, 2008) was an American dancer and actress.
Document 5: Broadway Melody of 1940: Broadway Melody of 1940 is a 1940 MGM movie musical starring Fred Astaire, Eleanor Powell and George Murphy. It was directed by Norman Taurog and features music by Cole Porter, including "Begin the Beguine".
Document 6: This Heart of Mine: "This Heart of Mine" is a 1946 song. This music standard was written by composer Harry Warren and lyricist Arthur Freed to be featured in the musical film score "Ziegfeld Follies". This song is introduced by Fred Astaire who danced with Lucille Bremer in a lavish and romantic dance. In the same film, Esther Williams swam in a water ballet to a softer, instrumental version of the song. Judy Garland and Maxine Sullivan have also recorded this song.
Document 7: Vera-Ellen: Vera-Ellen (born Vera-Ellen Westmeier Rohe; February 16, 1921 – August 30, 1981) was an American dancer and actress, principally
Document 8: Audrey Hepburn: Audrey Hepburn ( ; born Audrey Kathleen Ruston; May 4, 1929January 20, 1993) was a British actress, model, dancer and humanitarian. Recognized as a film and fashion icon, Hepburn was active during Hollywood's Golden Age. She was ranked by the American Film Institute as the third-greatest female screen legend in Golden Age Hollywood and was inducted into the International Best Dressed List Hall of Fame.
Document 9: Harry Warren: Harry Warren (born Salvatore Antonio Guaragna, December 24, 1893 – September 22, 1981) was an American composer and lyricist. Warren was the first major American songwriter to write primarily for film. He was nominated for the Academy Award for Best Song eleven times and won three Oscars for composing "Lullaby of Broadway", "You'll Never Know" and "On the Atchison, Topeka and the Santa Fe". He wrote the music for the first blockbuster film musical, "42nd Street", choreographed by Busby Berkeley, with whom he would collaborate on many musical films.
Document 10: The Band Wagon: The Band Wagon is a 1953 musical comedy film directed by Vincente Minnelli, starring Fred Astaire and Cyd Charisse.  Fred Astaire was contemplating retirement just like his character. It tells the story of an aging musical star who hopes a Broadway show will restart his career. However, the play's director wants to make it a pretentious retelling of "Faust", and brings in a prima ballerina who clashes with the star. Along with "Singin' in the Rain", it is regarded as one of the finest of the Metro-Goldwyn-Mayer musicals, although it was only a modest box-office success on first release.
Document 11: The Belle of New York (1952 film): The Belle of New York is a 1952 Metro-Goldwyn-Mayer Hollywood musical comedy film set in New York circa 1900 and stars Fred Astaire, Vera-Ellen, Alice Pearce, Marjorie Main, Gale Robbins and Keenan Wynn, with music by Harry Warren and lyrics by Johnny Mercer. The film was directed by Charles Walters.
Document 12: Funny Face: Funny Face is a 1957 American musical romantic comedy film directed by Stanley Donen and written by Leonard Gershe, containing assorted songs by George and Ira Gershwin. Although having the same title as the 1927 Broadway musical "Funny Face" by the Gershwin brothers, and featuring the same male star (Fred Astaire), the plot is totally different and only four of the songs from the stage musical are included. Alongside Astaire, the film stars Audrey Hepburn and Kay Thompson.
Document 13: Lucille Bremer: Lucille Bremer (February 21, 1917 – April 16, 1996) was an American film actress and dancer.
Document 14: Vera Michelena: Vera Michelena (June 16, 1885 – August 28, 1961) was a Venezuelan American actress, contralto prima donna and dancer who appeared in light opera, musical comedy, vaudeville and silent film. She was perhaps best remembered for her starring rôles in the musicals "The Princess Chic", "Flo Flo" and "The Waltz Dream", her rendition of the vampire dance in the musical "Take It From Me" and as a "Ziegfeld Follies" performer.
Document 15: The Kid from Brooklyn: The Kid from Brooklyn is a 1946 American musical comedy film directed by Norman Z. McLeod and starring Danny Kaye, Virginia Mayo, Vera-Ellen, Steve Cochran, Walter Abel, Eve Arden, and Fay Bainter. Virginia Mayo's and Vera-Ellen's singing voices were dubbed by Betty Russell and Dorothy Ellers, respectively,
ground_truth: Vera-Ellen