It seems not all these contra-indicators apply to Loma Linda, CA as well. From articles linked, most other area candidates are long dead, pension fraud, in low

It seems not all these contra-indicators apply to Loma Linda, CA as well. From articles linked, most other area candidates are long dead, pension fraud, in low income areas, also affecting some areas in the U.S., but mostly relating to records keeping. Meanwhile: “In the United States, supercentenarian status is predicted by the absence of vital registration. ... Only 18% of ‘exhaustively’ validated supercentenarians have a birth certificate, falling to zero percent in the USA ... 82% of supercentenarian records from the USA predate state-wide birth certification.” However, in the research graphics, Loma Linda is not on the map depicting concentrations in midwest. There are these mentions, however: “Centres for Disease Control generated an independent estimate of average longevity across the USA: they found that Loma Linda, a Blue Zone supposedly characterised by a ‘remarkable’ average lifespan 10 years above the national average, instead has an unremarkable average lifespan (27th-75th percentile; Fig S6)”, “The two remaining blue zones, Loma Linda and the Nicoya Peninsula, are considered exceptional due to their high average longevity rather than the presence of the oldest-old.”, and “However, when assessed independently by the Centers for Disease Control (CDC) the five small-area survey tracts covering Loma Linda instead have an average life expectancy of 76 to 81 years: the 27th to 75th percentiles of US life expectancy (Fig S6). This means, at best, the independent CDC estimates rank Loma Linda as the 16,101st most long-lived neighborhood in the USA (Fig. S6; S1 code). As such, it is again unclear why the lifespan of this community has been considered remarkable.” Till now, this area stood out as an odd duck among the blue zones, being an otherwise regular U.S. suburb, just high prevalence of longevity among the vegetarian health conscious non-smoker non-drinker types. Most of the other zones attribute health to hills and seafood, while now seeming poverty and pension fraud related. Long before the study and term became popularized, it was noted that among one community in and around this CA area (including great grandmothers or aunts that had moved to mountain communities in other parts of CA), seemingly unusual numbers of women among extended family and friends' extended family lived over 100. Though less so since 2010s, as though most were of generations from 1860s - 1900s. Incidentally, the directly known individuals who passed on in '80s or '90s did have birth certificates and carefully documented genealogies dating back to 1400s - 1600s or so. Putting two and two together, while Loma Linda is not mentioned other than these quotes, it seems the suggestion here is that these western-most U.S. clusters could be late 1800s births in areas not yet organized for birth certificates and records keeping, still around to be noticed in the 1970s to 2010s. TL;DR: This makes it seem as though someone trying to make a case for the longevity of a small set of people misunderstood or overlooked the error rates at play and didn't dig further, allowing them to make a case for a zone-wide phenomenon.