In memoriam Charles E Land, 1937–2018

Dr Charles E Land, a world-renowned statistician in radiation risk analysis, died on 25 January 2018. He was 80 years old. Dr Land’s vital contributions to the radiation field are numerous. He was among the first to lay groundwork for understanding the pattern of radiation risk for breast cancer, estimating radiation risk at low doses, and developing methods for quantitative uncertainty analysis. I first met Dr Land during a 1998 interview at the Radiation Epidemiology Branch (REB), US National Cancer Institute (NCI), when he was already an established researcher. My first impression of him, which only strengthened over the years, was that he was a very thoughtful scientist and kind person. Later, I was fortunate to be mentored by Dr Land and collaborate with him on many projects. Dr Land was born in San Francisco in 1937. He received his B.A. degree in psychology from the University of Oregon in 1959 and M.A. and PhD in statistics from the University of Chicago in 1964 and 1968. In his PhD thesis, Dr Land developed a method for calculating uniformly the most accurate unbiased exact confidence limits for the mean of a lognormal distribution. It is known as the ‘Land method’ and is currently a default method in many statistical software packages. Dr Land’s career in radiation risk analysis began in 1966 when he accepted a position as research associated statistician at the Atomic Bomb Casualty Commission (ABCC) in Hiroshima, Japan. Dr Land spent two two-year terms at the ABCC (1966–1968) and its successor, Radiation Effects Research Foundation (RERF, 1973–1975). The very first paper published in 1971 with Drs Beebe and Kato evaluated mortality for a wide range of causes of death in atomic bomb survivors by applying the first dosimetry system to assess pattern of dose-response and its differences by sex, age, and time [1]. This pioneering work undoubtedly had to influence Dr Land’s later views on low dose risk estimation. After returning to the US in 1975, Dr Land joined NCI becoming one of the ‘founding fathers’ of the REB. During his career at NCI, which spanned 34 years, he continued collaborating on the Life Span Studies of Japanese atomic bomb survivors. At one of the conferences, Dr Land met Dr Tokunaga, a RERF pathologist who had been systematically collecting pathological records and specimens of breast cancer cases from Hiroshima and Nagasaki hospitals. This was the beginning of a long-lasting collaboration and personal friendship. Through rigorous pathological review and statistical analysis, their approach became a model for other tissue-specific studies now routinely conducted at RERF. In a series of seminal breast cancer papers [2–6], Drs. Land and Tokunaga demonstrated that the radiation excess relative and absolute risks of breast cancer increased as age at exposure decreased [2]. They also found high radiation risks for early onset breast cancers (<35 years) [3, 5] and, in their last joint publication [6], reported that both age at exposure and attained age were important modifiers of radiation risks. Another principal contribution to the field of radiation-related breast cancer was the Dr Land-conducted study of interaction between radiation exposure and reproductive factors in which he demonstrated the multiplicative rather than additive nature of interaction with age at first full term pregnancy, number of births, and cumulative lactation history [7, 8]. | Society for Radiological Protection Journal of Radiological Protection