The study by Cohen et al. (1997) aimed to investigate the hypothesis that diverse social ties to friends, family, work, and community are associated with increased resistance to infection. The research involved 276 healthy volunteers aged 18 to 55 years who were quarantined and given nasal drops containing either rhinovirus 39 or Hanks. The results showed that those with more types of social ties were less susceptible to common colds, produced less mucus, had better nasal mucociliary clearance, and shed less virus. The association between social network diversity and resistance to colds was dose-response, with an adjusted relative risk of 4.2 comparing those with fewest (1-3) to those with most (6 or more) types of social ties. Smoking, poor sleep quality, alcohol abstinence, low dietary intake of vitamin C, elevated catecholamine levels, and introversion were also associated with greater susceptibility but could only partially account for the relationship between social network diversity and cold incidence. The study concluded that more diverse social networks were associated with greater resistance to upper respiratory illness.The study by Cohen et al. (1997) aimed to investigate the hypothesis that diverse social ties to friends, family, work, and community are associated with increased resistance to infection. The research involved 276 healthy volunteers aged 18 to 55 years who were quarantined and given nasal drops containing either rhinovirus 39 or Hanks. The results showed that those with more types of social ties were less susceptible to common colds, produced less mucus, had better nasal mucociliary clearance, and shed less virus. The association between social network diversity and resistance to colds was dose-response, with an adjusted relative risk of 4.2 comparing those with fewest (1-3) to those with most (6 or more) types of social ties. Smoking, poor sleep quality, alcohol abstinence, low dietary intake of vitamin C, elevated catecholamine levels, and introversion were also associated with greater susceptibility but could only partially account for the relationship between social network diversity and cold incidence. The study concluded that more diverse social networks were associated with greater resistance to upper respiratory illness.