Kanagawa Investigation of the Total Check-up Data from the National database (KITCHEN): protocol for data-driven population-based repeated cross-sectional and 6-year cohort studies

Abstract

IntroductionThe unmitigated incidence of cardiometabolic diseases, such as type 2 diabetes and metabolic syndrome, has gained attention in Japan. ‘Big data’ can be useful to clarify conflicting observations obtained from studies with small samples and about rare conditions that are often neglected. We epidemiologically address these issues using data from health check-ups conducted in Kanagawa Prefecture, the prefecture with the second largest population in Japan, in the Kanagawa Investigation of the Total Check-up Data from the National Database (KITCHEN).Methods and analysisThis research consists of a series of population-based cross-sectional studies repeated from 2008–2014 and 6-year cohort studies. Since 2017, we have reviewed the data of people living in Kanagawa Prefecture who underwent a health check-up mainly for general health and the prevention of metabolic syndrome. The sample size ranges from 1.2 million to 1.8 million people in the cross-sectional studies and from 370 000 to 590 000 people in the cohort studies. These are people aged 40–74 years, whose clinical parameters were measured and who responded individually to a questionnaire. We investigate potential associations and causalities of various aetiologies, including diabetes and metabolic syndrome, using clinical data and lifestyle information. With multidisciplinary analysis, including data-driven analysis, we expect to obtain a wide range of novel findings, to confirm indeterminate previous findings, especially in terms of cardiometabolic disease, and to provide new perspectives for human health promotion and disease prevention.Ethics and disseminationEthical approval was received from the Ethics Committee of Kanagawa University of Human Services (10-43). The protocol was approved in December 2016 by the Japanese Ministry of Health, Labour and Welfare (No. 121). The study results will be disseminated through open platforms including journal articles, relevant conferences and seminar presentations.

High Serum Aspartate Aminotransferase, Underweight, and Weight Loss in Older People: Results of the KITCHEN-4

“…To date, there is no hematological biochemical marker for being underweight, WL, or UWWL, which can reflect sarcopenia and/or frailty. In Japan and most developed countries worldwide, serum AST and ALT are routinely measured in the clinical setting and at annual regular checkups, and the process is inexpensive, time-efficient, and exhibits good reproducibility [16].…”

“…The present investigation was a composite study using health checkup data acquired in Japan as part of the Kanagawa Investigation of the Total Checkup Data from the National Database (KITCHEN), which is a broader study aimed at elucidating factors associated with cardiometabolic diseases. The design of that study is described in detail elsewhere [16]. Since 2008, all people living in Japan aged 40 to 74 years are supposed to undergo a yearly itemized health checkup managed by the Ministry of Health, Labour and Welfare (MHLW) [17].…”

“…BMI and other measurements were conducted in the morning after an overnight fast. Clinical biochemical parameters including AST, ALT, and GGT were measured using internal and external standards, in accordance with the HMWL [16]. Being underweight concomitant with WL (UWWL) was defined as exhibiting a BMI < 18.5 concomitant with a reduction in body weight of ≥5% compared to baseline body weight (≥5% WL) [3,[21][22][23].…”

Trace Proteinuria and the Incidence of Overt Proteinuria After Five Years: Results of the Kanagawa Investigation of the Total Checkup Data From the National Database-5 (KITCHEN-5)

“…This original study aimed to determine factors associated with cardiometabolic diseases. The study design is described in detail elsewhere [ 8 ]. Since 2008, all people living in Japan aged 40 - 74 years are supposed to undergo a yearly specific health checkup managed by the Ministry of Health, Labour and Welfare (MHLW) [ 9 ].…”

“…Unfortunately, the data of estimated glomerular filtration rate (eGFR) and measurements related to urine specimens were unavailable in our database because this checkup had started for the screening of metabolic syndrome [ 8 ], although it is well known at present time that metabolic syndrome and cardiovascular disease are closely associated with impaired kidney function [ 12 , 13 ].…”