London has the lowest concentration of people aged over 50 but it also has the highest levels of dissatisfaction, according to research by public sector analysts Experian.
It showed London areas have the nine lowest concentrations of people aged over 50 in England.
But the capital's boroughs make up the bottom 10 in this age group's satisfaction with social cohesion.
The city also has seven areas in the bottom 10 for approval of home care.
The research for the BBC shows the capital's over-50 population fell between 1999 and 2009.
The research found Hammersmith and Fulham, Camden, Lewisham, Haringey, Lambeth, Islington, Newham, Southwark, Hackney and Tower Hamlets made up the bottom 10 areas in England for people not satisfied with community cohesion, where this age group replied negatively to the question: "Do neighbours look out for each other?"
Tower Hamlets had 29.2% of its over-50 residents saying there was no social cohesion.
Gordon Deuchars, from Age Concern London, said: "Living in a fast moving and anonymous city can be tough on all of us but it can be especially alienating for London's 890,000 older people.
"Maintaining a sense of community is extremely important and we are really concerned that local spending cuts may mean community centres and local groups, which are a real life-line for older Londoners, could be forced to close."
And London did not fare much better when it came to this age group's satisfaction with home care.
The areas of Islington, Newham, Southwark, Merton, Lambeth, Haringey and Camden came in the bottom 10.
"Many older Londoners have lived in this city their whole lives and have no wish to move elsewhere," Mr Deuchars said.
"It is absolutely vital that their city does not forget about them and the resources they need to stay active and involved are protected."