Appendix A - Mortality by Occupation, Industry, and Cause of Death: 24 Reporting States (1984-1988)
DHHS (NIOSH) PUBLICATION
NO. 97-114 JUNE 1997
Appendix A
Technical Notes
Data shown in this report are based on information for deaths occurring in 24 reporting States for at least one of the years during the period 1984-88 (Table A-1).
These mortality data are based on information from the original death certificates received in the State registration offices. Except for the occupation and industry information, the demographic information was based on State-coded data provided on computer tape to NCHS through the Vital Statistics Cooperative Program (VSCP) (except information for Georgia for 1984 that was coded by NCHS). Occupation and industry were coded by the States and were provided on computer tape to NCHS through purchase orders. The medical information was State-coded and provided on computer tape to NCHS through the VSCP by Alaska (1988), Colorado, Idaho, Kansas, Maine, Nebraska, New Hampshire, North Carolina, South Carolina, Vermont, and Wisconsin. Based on copies of the original death certificates, NCHS coded the medical information for Alaska (1987), Georgia, Indiana, Kentucky, Missouri, Nevada, New Jersey, New Mexico, Ohio, Oklahoma, Rhode Island, Tennessee, and Utah.
Mortality data in this report refer to all deaths of residents in the 24-State reporting area that occurred in that area.
OCCUPATION AND INDUSTRY ITEMS ON DEATH CERTIFICATEThe information in this report is based on occupation and industry entries on the Standard Certificate of Death that were responses to the questions in items 14a (Usual Occupation [Give kind of work done during most of the working life, even if retired]) and 14b (Kind of business or industry) (Figure A-1, Figure A-1 continued).
The Standard Certificate of Death is issued by the Public Health Service as a means of attaining uniformity in the content of vital statistics information collected by the States. While the certificates in each State may differ somewhat from the Standard to the extent required by the needs of the State or by special provisions of the State vital statistics law, the certificates of most States conform closely in content and arrangement to the Standard.
CLASSIFICATION OF OCCUPATION AND INDUSTRYOccupation and industry information from the death certificate is classified according to the Bureau of the Census Alphabetical Index of Industries and Occupations.21) The information is coded using a special adaptation of the occupation and industry coding instructions used by the Bureau of the Census for information reported on censuses and surveys. The instructions, used by NCHS and the reporting States, are in the NCHS Instruction Manual, Part 19, Industry and Occupation Coding for Death Certificates.50)
For this report, the 503 Bureau of the Census occupations and 6 other occupation categories (Armed Forces; Retired; Housewives, homemakers; Students; Volunteers; and Unemployed, never worked, disabled) were grouped into 325 occupation categories for analysis (List A-1). The analyses also included all 231 Bureau of the Census industry categories plus 3 other industry categories (Armed Forces, Retired, and Homemaker, Student, Unemployed, Volunteer) for a total of 235 industries (List A-2).
CAUSE-OF-DEATH CLASSIFICATION
The mortality statistics in this report were compiled in accordance with the World Health Organization (WHO) regulations, which specify that member nations classify causes of death by the current Manual of the International Statistical Classification of Diseases, Injuries, and Causes of Death.22 Causes of death for 1984-88 were classified according to the Ninth Revision of the International Classification of Diseases.22
In addition to specifying the classification, the WHO regulations outline the form of the medical certification and the procedures to be used in coding cause of death. Cause-of-death data presented in this publication were coded by procedures outlined in the annual issues of Part 2a of the NCHS Instruction Manual. 51
CAUSE-OF-DEATH LIST
For analysis of occupation and industry mortality data, a special list of 192 causes of death (List A-3) was developed jointly by NIOSH and NCHS. Of the 192 causes, 185 were analyzed for males and 188 for females. This list was created keeping in mind those causes of death that might possibly be associated with occupational exposures, particularly malignant neoplasms of selected sites and numerous accidental death categories.
QUALITY CONTROL
Quality control for the occupation and industry (O/I) coding was conducted by NCHS. For each year, States that maintained an error rate of less than 10% for the year and had less than 10% of their records coded to Retired or Unknown were included in the analysis. All 24 States met the criteria for at least 1 year. See Table 1 in the main text for the number and percentage distribution of the records coded to Retired or Unknown.
PMRs AND SIGNIFICANCE TESTING
The computer program for computing PMRs and statistical tests was developed by NIOSH. The PMR does not make use of a population at risk and, therefore, is not equivalent to a death rate. The PMR for an occupation (industry) indicates whether the proportion of deaths attributed to a particular cause of death is higher (greater than 100) or lower (less than 100) than the corresponding proportion for all occupations (industries) combined. In this report, PMRs are age-adjusted for white males, black males, white females, and black females.
PMRs for the four race-sex groups were computed using Table A-2 for a specific age group.
When the total observed number of deaths, , are greater than 1,000, the following methods are used. The observed number of deaths, Ai, are assumed to be binomially distributed with parameters N1i and M1i/Ti. Under the null hypothesis (H0:PMR=100), the mean of the is and the variance is
The distribution of the is unknown but can be assumed to be approximately normally distributed. Thus, hypotheses can be tested using the following statistic:which is assumed to have a standard normal distribution. This formula is equivalent to statistically testing the hypothesis (H0: PMR=100), by using the following Mantel-Haenszel (M-H) chi-square test with one-degree of freedom:52
It should be noted for this study that this formula excludes the correction for continuity. A PMR is significantly different from 100 at the 0.05 level if the computed M-H chi-square is greater than or equal to 3.84.
When the total observed number of deaths, , is greater than 1,000, the upper and lower 95% confidence limits are computed in the following way:
When the total observed number of deaths, , is equal to or less than 1,000, the following methods are used. Since the Ai's are distributed approximately as Poisson random variables, the Ais are also distributed approximately as a Poisson random variable. Under the null hypothesis (H0: PMR=100), the mean and variance of the Ai is E(Ai). Therefore, exact two-sided tests based on the Poisson distribution are used to determine if the Ai is significantly different from the E( Ai) (or equivalently, if the PMR is significantly different from 100).53)
When the total observed number of deaths, , is equal to or less than 1,000, the 95% confidence limits of a PMR are determined in the following way. Denote the mean of to be . Then the confidence limits for the PMR ( / ) are determined by obtaining exact confidence limits for and dividing the resulting end points by . Let the lower limit on be denoted by L and the upper limit by U. The 95% CI represents all possible values of which satisfy the following two inequalities:54)
Thus L and U were obtained from the following equations:
When these two end points are divided by E(Ai) and multiplied by 100, this determines a 95% CI that will cover 100 if and only if the hypothesis test with = 0.05 is not significant.
It should be noted that the criterion for PMRs to be shown in this report is that the PMR for a cause of death and an occupation (industry) had to be 120 or more and statistically significantly higher than 100 and had to have 10 or more observed deaths for the group aged 20 and over for a particular race-sex group. All other PMRs are available upon request.
Caution should be exercised in interpreting statistically significant PMRs. Since approximately 430,000 PMRs were statistically tested, about 5% (about 21,500) would be expected to be statistically significant at least at the .05 level, just due to chance (if the tests were independent).55)
PUBLIC-USE DATA TAPESBeginning with data for 1985, mortality public-use data tapes include information about the occupation and industry of the decedent, along with other coded demographic and medical information. The detailed contents of the mortality data tapes and other public-use data tapes from NCHS are described in the NCHS publication Catalog of Electronic Data Products.56 The 1985-93 mortality public-use data tapes may be purchased from the following:
National Technical Information Service
U.S. Department of Commerce
Springfield, Virginia 22161, (703) 487-4650
1 Numbers after occupations are Bureau of the Census category numbers of the Classified Index
of Industries and Occupations, 1982.
2 n.e.c.=not elsewhere classified
3 Occupation groups constructed for coding death certificate information.
List A-2: 235 Industries4
Agricultural production, livestock (011)
Agricultural services, except horticultural (020)
Horticultural services (021)
Forestry (030)
Fishing, hunting, and trapping (031)
Metal mining (040)
Coal mining (041)
Crude petroleum and natural gas extraction (042)
Nonmetallic mining and quarrying, except fuel (050)
Construction (060)
Meat products (mfg)5 (100)
Dairy products (mfg) (101)
Canned and preserved fruits and vegetables (mfg) (102)
Grain mill products (mfg) (110)
Bakery products (mfg) (111)
Sugar and confectionery products (mfg) (112)
Beverage industries (mfg) (120)
Miscellaneous food preparations and kindred products (mfg) (121)
Not specified food industries (mfg) (122)
Tobacco manufactures (130)
Knitting mills (mfg) (132)
Dyeing and finishing textiles, except wool and knit goods (mfg) (140)
Floor coverings, except hard surface (mfg) (141)
Yam, thread, and fabric mills (mfg) (142)
Miscellaneous textile mill products (mfg) (150)
Apparel and accessories, except knit (mfg) (151)
Miscellaneous fabricated textile products (mfg) (152)
Pulp, paper, and paperboard mills (mfg) (160)
Miscellaneous paper and pulp products (mfg) (161)
Paperboard containers and boxes (mfg) (162)
Newspaper publishing and printing (171)
Printing, publishing and allied industries, except newspapers (172)
Plastics, synthetics, and resins (mfg) (180)
Drugs (mfg) (181)
Soaps and cosmetics (mfg) (182)
Paints, varnishes, and related products (mfg) (190)
Agricultural chemicals (mfg) (191)
Industrial and miscellaneous chemicals (mfg) (192)
Petroleum refining (200)
Miscellaneous petroleum and coal products (mfg) (201)
Tires and inner tubes (mfg) (210)
Other rubber products, and plastics footwear and belting (mfg) (211)
Miscellaneous plastics products (mfg) (212)
Leather tanning and finishing (mfg) (220)
Footwear, except rubber and plastic (mfg) (221)
Leather products, except footwear (mfg) (222)
Logging (230)
Sawmills, planing mills, and millwork (231)
Wood buildings and mobile homes (mfg) (232)
Miscellaneous wood products (mfg) (241)
Furniture and fixtures (mfg) (242)
Glass and glass products (mfg) (250)
Cement, concrete, gypsum, and plaster products (mfg) (251)
Structural clay products (mfg) (252)
Pottery and related products (mfg) (261)
Miscellaneous nonmetallic mineral and stone products (mfg) (262)
Blast furnaces, steelworks, rolling and finishing mills (mfg) (270)
Iron and steel foundries (mfg) (271)
Primary aluminum industries (mfg) (272)
Other primary metal industries (mfg) (280)
Cutlery, hand tools, and other hardware (mfg) (281)
Fabricated structural metal products (mfg) (282)
Screw machine products (mfg) (290)
Metal forgings and Stampings (mfg) (291)
Ordnance (mfg) (292)
Miscellaneous fabricated metal products (mfg) (300)
Not specified metal industries (mfg) (301)
Engines and turbines (mfg) (310)
Farm machinery and equipment (mfg) (311)
Construction and material handling machines
(mfg) (312)
Metalworking machinery (mfg) (320)
Office and accounting machines (mfg) (321)
Electronic computing equipment (mfg) (322)
Machinery, except electrical, n.e.c.6 (mfg) (331)
Not specified machinery (mfg) (332)
Household appliances (mfg) (340)
Radio, TV, and communication equipment (mfg) (341)
Electrical machinery, equipment, and supplies, n.e.c. (mfg) (342)
Not specified electrical machinery, equipment and
supplies (mfg) (350)
Motor vehicles and motor vehicle equipment (mfg) (351)
Aircraft and parts (mfg) (352)
Ship and boat building and repairing (mfg) (360)
Railroad locomotives and equipment (mfg) (361)
Guided missiles, space vehicles, and parts (mfg) (362)
Cycles and miscellaneous transportation equipment (mfg) (370)
Scientific and controlling instruments (mfg) (371)
Optical and health services supplies (mfg) (372)
Photographic equipment and supplies (mfg) (380)
Watches, clocks, and clockwork operated devices (mfg) (381)
Not specified professional equipment (mfg) (382)
Toys, amusement, and sporting goods (mfg) (390)
Miscellaneous manufacturing industries (391)
Not specified manufacturing industries (392)
Railroads (400)
Bus service and urban transit (401)
Taxicab service (402)
Trucking service (410)
Warehousing and storage (411)
U.S. Postal Service (412)
Water transportation (420)
Air transportation (421)
Pipe lines, except natural gas (422)
Services incidental to transportation (432)
Radio and television broadcasting (440)
Telephone (wire and radio) (441)
Telegraph and miscellaneous communication services (442)
Electric light and power (460)
Gas and steam supply systems (461)
Electric and gas, and other combinations (462)
Water supply and irrigation (470)
Sanitary services (471)
Not specified utilities (472)
Motor vehicles and equipment (whls)7 (500)
Furniture and home furnishings (whls) (501)
Lumber and construction materials (whls) (502)
Sporting goods, toys, and hobby goods (whls) (510)
Metals and minerals, except petroleum (whis) (511)
Electrical goods (whls) (512)
Hardware, plumbing and heating supplies (whls) (521)
Not specified electrical and hardware products (whls) (522)
Machinery, equipment, and supplies (whls) (530)
Scrap and waste materials (whls) (531)
Miscellaneous wholesale, durable goods (whls) (532)
Paper and paper products (whls) (540)
Drugs, chemicals, and allied products (whls) (541)
Apparel, fabrics, and notions (whls) (542)
Groceries and related products (whls) (550)
Farm-product raw materials (whls) (551)
Petroleum products (whls) (552)
Alcoholic beverages (whis) (560)
Farm supplies (whis) (561)
Miscellaneous wholesale, nondurable goods (562)
Not specified wholesale trade (571)
Lumber and building material retailing (580)
Hardware stores (581)
Retail nurseries and garden stores (582)
Mobile home dealers (590)
Department stores (591)
Variety stores (592)
Miscellaneous general merchandise stores (600)
Grocery stores (601)
Dairy products stores (602)
Retail bakeries (610)
Food stores, n.e.c. (611)
Motor vehicle dealers (612)
Auto and home supply stores (620)
Gasoline service stations (621)
Miscellaneous vehicle dealers (622)
Apparel and accessory stores, except shoe (630)
Shoe stores (631)
Furniture and home furnishings stores (632)
Household appliances, TV, and radio stores (640)
Eating and drinking places (641)
Drug stores (642)
Liquor stores (650)
Sporting goods, bicycles, and hobby stores (65 1)
Book and stationery stores (652)
Jewehy stores (660)
Sewing, needlework, and piece goods stores (661)
Mail order houses (662)
Vending machine operators (670)
Direct selling establishments (671)
Fuel and ice dealers (672)
Retail florists (681)
Miscellaneous retail stores (682)
Not specified retail trade (691)
Banking (700)
Savings and loan associations (701)
Credit agencies, n.e.c. (702)
Security, commodity brokerage, and investment companies (710)
Insurance (711)
Real estate, including real estate-insurance-law offices (712)
Advertising (721)
Services to dwellings and other buildings (722)
Commercial research, development, and testing labs (730)
Personnel supply services (73 1)
Business management and consulting services (732)
Computer and data processing services (740)
Detective and protective services (741)
Business services, n.e.c. (742)
Automotive services, except repair (750)
Automotive repair shops (75 1)
Electrical repair shops (752)
Miscellaneous repair shops (760)
Private households (761)
Hotels and motels (762)
Lodging places, except hotels and motels (770)
Laundry, cleaning, and garment services (771)
Beauty shops (772)
Barber shops (780)
Funeral service and crematories (781)
Shoe repair shops (782)
Dressmaking shops (790)
Miscellaneous personal services (791)
Theaters and motion pictures (800)
Bowling alleys, billiard and pool parlors (801)
Miscellaneous entertainment and recreation services (802)
Offices of physicians (812)
Offices of dentists (820)
Offices of chiropractors (821)
Offices of optometrists (822)
Offices of health practitioners, n.e.c. (830)
Hospitals (831)
Nursing and personal care facilities (832)
Health services, n.e.c. (840)
Legal services (841)
Elementary and secondary schools (842)
Colleges and universities (850)
Business, trade, and vocational schools (851)
Libraries (852)
Educational services, n.e.c. (860)
Job training and vocational rehabilitation services (861)
Child day care services (862)
Residential care facilities, without nursing (870)
Social services, n.e.c. (871)
Museums, art galleries, and zoos (872)
Religious organizations (880)
Membership organizations (881)
Engineering, architectural, and surveying services (882)
Accounting, auditing, and bookkeeping services (890)
Noncommercial educational and scientific research (891)
Miscellaneous professional and related services (892)
Executive and legislative offices (900)
General government, n.c.c. (901)
Justice, public order, and safety (910)
Public finance, taxation, and monetary policy (921)
Adniinistration of human resources programs (922)
Administration of environmental quality and housing programs (930)
Administration of econo@c programs (931)
National security and international affairs (932)
Armed forces (942)8
Retired (95 I)8
Homemaker, student, unemployed, volunteer (961)8
Industry not reported (990)
4 Numbers after industries are Bureau of the Census category numbers of the Classified Index of Industries and Occupations, 1982.
5 mfg = manufacturing industry
6 n.e.c. = not elwwhere classified
7 whls = wholesale trade
8 Industry groups constructed for coding death certificate information
List A-3: 192 Selected Causes of Death9
9 Numbers after causes of death are category numbers of the Ninth Revision of the Intemational Classification of Diseases, 1975.
10 Boldface indicates that this category was not included in the analysis.
11 A constructed category including mental disorders and other diseases and conditions related to alcohol consumption.
12 Not included within broad category.
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