A study has found that countries with more pet cats tend to have happier people. It did not prove a causal relationship that keeping a cat raises an individual’s happiness.

Gigazine, a Japanese media outlet, reported on Oct. 5 that researchers in Mexico, Finland, Latvia and the United States analysed relationships among happiness levels in 93 countries and cat density, gross domestic product (GDP), income levels, healthcare spending and toxoplasma prevalence. The findings were published in the international academic journal PLOS One.

The analysis found that countries with more cats per 10,000 people tended to have higher happiness levels. The correlation coefficient between cat density and happiness was 0.620. By contrast, the prevalence of IgM antibodies, indicating recent toxoplasma infection, showed a negative correlation with happiness of minus 0.540. In a model that analysed multiple variables together, cat density showed a positive relationship with happiness and IgM prevalence showed a negative one.

One notable point was that toxoplasma exposure was not necessarily higher in countries with many cats. The researchers estimated that wealthier countries often keep cats indoors, feed them processed pet food and provide regular veterinary care, which could lower the likelihood of infection. In low- and middle-income countries, they said cats are relatively more likely to roam freely outdoors, which could raise the risk of environmental exposure.

The toxoplasma data have a limitation in that they used antibody prevalence among pregnant women, rather than the general public, as a proxy indicator for the total population. Cat density also does not show whether individuals actually own pet cats or their level of bonding. The researchers stressed that the results show correlations at the national level and do not mean that cats increase happiness or that toxoplasma reduces happiness.