We investigate a major turning point in mortality trends at adult ages that occurred for many low-mortality countries in the late 1960s or early 1970s. We analyze patterns of total and cause-specific mortality over the past 60 years using data from the Human Mortality Database and the World Health Organization. We focus on four broad categories of causes of death: heart diseases, cerebrovascular diseases, smoking-related cancers, and all other cancers. We use a two-slope regression model to assess the timing and magnitude of turning points in mortality trends over this era, making separate analyses by sex, age, and cause of death. The age pattern of temporal changes is given particular attention. Our results demonstrate convincingly that period-based factors were very significant in the onset of the "cardiovascular revolution" in the years around 1970. In general, although cohort processes cannot be ruled out as a driver of mortality change in recent decades (especially for mortality due to smoking-related cancers), the evidence reviewed here suggests that period factors have been the dominant force behind the mortality trends of high-income countries during this era.