Impact of Height and Weight on Life Span

Article excerpt

The entropy theory of aging predicts that increasing mass lowers life span, and hypothesizes that aging is the result of increasing disorder within the body [1]. This movement towards disorder or increased entropy is related to time, the mass of the body, its total energy content, and the nature of the mass and energy transactions.(a)

Among some groups in the USA, e.g., baseball players and famous people, the results of previous studies have suggested that increased height and weight are associated with decreased longevity [2, 3]. We therefore decided to study the relationships between these parameters in a different population sample.

The following hypothesis was investigated in the study: as humans become taller and proportionately heavier, their longevity decreases in proportion to their increase in height and absolute weight.

Materials and methods

The study subjects consisted of 373 male veterans who died between 1984 and 1988, mostly in the Veterans Administration (VA) Medical Center, San Diego, CA, USA.

Characteristics of the study sample

The ages at death of the individuals in the study ranged from 29 to 97 years. Both the mean heights and weights of the study population were within the norms for the USA: the mean height of the subjects was 175.3 cm, which is close to the national average for men in this age group, while the mean weight was 73.2 kg, which falls within the desirable weight range of 68.6-74.1 kg for men of height 175.3 cm and of average frame, as recommended by life insurance companies. The average age at death was 68.11 years, which is close to the life expectancy of 69.1 years for a man aged 25 years in 1940 (many of the men in the sample were roughly 25 years of age in 1940-43 and were in military service during this period). The body mass index (BMI) (weight (kg)/ [height.sup.2] ([m.sup.2])) for men of height [is less than or equal to] 175.3 cm was 22.9 and for men of height >175.3 cm, 23.1.

The causes of death were predominantly from age-related and alcohol-related illnesses, e.g., heart failure, cancer, stroke, and liver disease. A review of the causes of death indicates than cancer and heart disease deaths accounted for about the same proportion of tall and short men; however, shorter men were, on average, a few years older when they died from these diseases.

Because the proportion of females in the group was quite low, we included only males. Most subjects were Caucasians; Asians, Blacks and Hispanics represented about 7% of the 373 subjects.

Data collection

The data were obtained directly from each deceased patient's medical records. The data were recorded by one author and checked by the other. For each subject, height was recorded in inches and converted to cm, weight was measured in pounds and converted to kg, and the age at death was calculated by subtracting the date of birth from the date of death. As in conventional usage, a person was considered to be at a given age from one birthday to the next. The heights and weights were obtained from notes made by the nutritionists, who obtained the data from the nursing staff. Nursing practice at the VA Medical Center is to weigh each patient on admission. However, each individual was asked to state his height, and only if he did not know or seemed uncertain was it then measured.

Hospital records were obtained unselectively. Records of deceased patients were examined by one author, who started at the left end of the shelf where the records were stored and examined each in succession until recording was completed for that day. The other author then scrutinized the same files and verified the data recorded.

Statistical tests

Pearson product-moment correlation coefficients were computed for height, weight, and age at death. Student's t-tests were used to compare the mean ages at death between men of height [is less than or equal to] 175. …