Lifetime<unk>  Lifetime<unk>  (LTP) is the proportion of individuals in a population that at some point in their life (up to the time of assessment) have experienced a "case", e.g., a disease; a traumatic event; or a behavior, such as committing a crime. Often, a 12-month<unk>  (or some other type of "period<unk> ") is provided in conjunction with lifetime<unk> . Point<unk>  is the<unk>  of disorder at a specific point in time (a month or less). Lifetime morbid risk is "the proportion of a population that might become afflicted with a given disease at any point in their lifetime." Period<unk>  Period<unk>  is the proportion of the population with a given disease or condition over a specific period of time. It could describe how many people in a population had a cold over the cold season in 2006, for example. It is expressed as a percentage of the population and can be described by the following formula: Period<unk>  (proportion) = Number of cases that existed in a given period ÷ Number of people in the population during this period The relationship between incidence (rate), point<unk>  (ratio) and period<unk>  (ratio) is easily explained via an analogy with photography. Point<unk>  is akin to a flashlit photograph: what is happening at this instant frozen in time. Period<unk>  is analogous to a long exposure (seconds, rather than an instant) photograph: the number of events recorded in the photo whilst the camera shutter was open. In a movie each frame records an instant (point<unk> ; by looking from frame to frame one notices new events (incident events) and can relate the number of such events to a period (number of frames); see incidence rate. Point<unk>  Point<unk>  is a measure of the proportion of people in a population who have a disease or condition at a particular time, such as a particular date. It is like a snapshot of the disease in time. It can be used for statistics on the occurrence of chronic diseases. This is in contrast to period<unk>  which is a measure of the proportion of people in a population who have a disease or condition over a specific period of time, say a season, or a year. Point<unk>  can be described by the formula:<unk>  = Number of existing cases on a specific date ÷ Number of people in the population on this date
Prevalence
Incidence 
Risk factor
Mortality rate
Infection rate
Case fatality rate
Risk of mortality
Threshold limit value