A study in Rotterdam (European Journal of Heart Failure, vol. 11, 2009, pp. 922–928) followed the health of 7983 subjects over 20 years to determine whether intake of fish could be associated with a decreased risk of heart failure in a general population of men and women aged 55 years and older. Results showed that the dietary intake of fish was not significantly related to heart failure incidence. Even for a high daily fish consumption of more than 20 grams a day there appeared no added protection against heart failure. Incidence rates were similar in those who consumed no fish (incidence rate of 11 per 1000), moderate fish (median 9 g per day, 12.3 per 1000) or high fish (9.9 per 1000). The relative risk of heart failure in the high intake groups (medium and high fish) was 0.96 when compared with no intake with a 95% confidence interval of (0.78, 1.18). Explain how to interpret the
(a) Reported relative risk.
(b) Confidence interval for the relative risk.